diff --git a/ui/src/Components/AlertAck/index.js b/ui/src/Components/AlertAck/index.js
index 17a1fbd82..4f6839bc5 100644
--- a/ui/src/Components/AlertAck/index.js
+++ b/ui/src/Components/AlertAck/index.js
@@ -192,7 +192,7 @@ const AlertAck = observer(
         .filter(([amName, alertCount]) => alertCount > 0)
         .map(([amName, _]) => amName);
       const clusters = Object.entries(
-        alertStore.data.upstreams.clusters
+        alertStore.data.clustersWithoutReadOnly
       ).filter(([clusterName, clusterMembers]) =>
         alertmanagers.some(m => clusterMembers.includes(m))
       );
diff --git a/ui/src/Components/AlertAck/index.test.js b/ui/src/Components/AlertAck/index.test.js
index 9512f7dd8..98b33af45 100644
--- a/ui/src/Components/AlertAck/index.test.js
+++ b/ui/src/Components/AlertAck/index.test.js
@@ -35,6 +35,7 @@ beforeEach(() => {
         name: "default",
         uri: "http://localhost",
         publicURI: "http://example.com",
+        readonly: false,
         headers: { foo: "bar" },
         error: "",
         version: "0.15.0",
@@ -287,6 +288,7 @@ describe("<AlertAck />", () => {
           name: "default",
           uri: "http://am1.example.com",
           publicURI: "http://am1.example.com",
+          readonly: false,
           headers: {},
           error: "",
           version: "0.15.0",
@@ -297,6 +299,7 @@ describe("<AlertAck />", () => {
           name: "fallback",
           uri: "http://am2.example.com",
           publicURI: "http://am2.example.com",
+          readonly: false,
           headers: {},
           error: "",
           version: "0.15.0",
@@ -334,6 +337,7 @@ describe("<AlertAck />", () => {
           name: "default",
           uri: "http://am1.example.com",
           publicURI: "http://am1.example.com",
+          readonly: false,
           headers: {},
           error: "",
           version: "0.16.2",
@@ -344,6 +348,7 @@ describe("<AlertAck />", () => {
           name: "fallback",
           uri: "http://am2.example.com",
           publicURI: "http://am2.example.com",
+          readonly: false,
           headers: {},
           error: "",
           version: "0.16.2",
@@ -381,6 +386,7 @@ describe("<AlertAck />", () => {
           name: "default",
           uri: "http://am1.example.com",
           publicURI: "http://am1.example.com",
+          readonly: false,
           headers: {},
           error: "",
           version: "0.15.0",
diff --git a/ui/src/Components/ManagedSilence/DeleteSilence.js b/ui/src/Components/ManagedSilence/DeleteSilence.js
index 20589f1db..ecac4df05 100644
--- a/ui/src/Components/ManagedSilence/DeleteSilence.js
+++ b/ui/src/Components/ManagedSilence/DeleteSilence.js
@@ -113,6 +113,7 @@ const DeleteSilenceModalContent = observer(
     getAlertmanager = () =>
       this.props.alertStore.data.upstreams.instances
         .filter(u => u.cluster === this.props.cluster)
+        .filter(u => u.readonly === false)
         .slice(0, 1)[0];
 
     parseAlertmanagerResponse = response => {
@@ -296,11 +297,16 @@ const DeleteSilence = observer(
         onModalExit
       } = this.props;
 
+      const members = alertStore.data.getClusterAlertmanagersWithoutReadOnly(
+        cluster
+      );
+
       return (
         <React.Fragment>
           <button
             className="btn btn-danger btn-sm"
-            onClick={this.toggle.toggle}
+            disabled={members.length === 0}
+            onClick={members.length && this.toggle.toggle}
           >
             <FontAwesomeIcon
               className="mr-1 d-none d-sm-inline-block"
diff --git a/ui/src/Components/ManagedSilence/DeleteSilence.test.js b/ui/src/Components/ManagedSilence/DeleteSilence.test.js
index 296b8d828..479104ba1 100644
--- a/ui/src/Components/ManagedSilence/DeleteSilence.test.js
+++ b/ui/src/Components/ManagedSilence/DeleteSilence.test.js
@@ -26,6 +26,7 @@ beforeEach(() => {
         name: "am1",
         cluster: "am",
         uri: "http://localhost:9093",
+        readonly: false,
         error: "",
         version: "0.15.3",
         headers: {}
diff --git a/ui/src/Components/ManagedSilence/SilenceComment.test.js b/ui/src/Components/ManagedSilence/SilenceComment.test.js
index 85163e669..f1f575a0e 100644
--- a/ui/src/Components/ManagedSilence/SilenceComment.test.js
+++ b/ui/src/Components/ManagedSilence/SilenceComment.test.js
@@ -44,6 +44,7 @@ const MockMultipleClusters = () => {
         name: "default",
         uri: "http://am1.example.com",
         publicURI: "http://am1.example.com",
+        readonly: false,
         headers: {},
         error: "",
         version: "0.15.0",
@@ -54,6 +55,7 @@ const MockMultipleClusters = () => {
         name: "fallback",
         uri: "http://am2.example.com",
         publicURI: "http://am2.example.com",
+        readonly: false,
         headers: {},
         error: "",
         version: "0.15.0",
@@ -64,6 +66,7 @@ const MockMultipleClusters = () => {
         name: "second",
         uri: "http://am3.example.com",
         publicURI: "http://am3.example.com",
+        readonly: false,
         headers: {},
         error: "",
         version: "0.15.0",
diff --git a/ui/src/Components/ManagedSilence/SilenceDetails.js b/ui/src/Components/ManagedSilence/SilenceDetails.js
index c5e33f236..68a9fffa6 100644
--- a/ui/src/Components/ManagedSilence/SilenceDetails.js
+++ b/ui/src/Components/ManagedSilence/SilenceDetails.js
@@ -65,6 +65,10 @@ const SilenceDetails = ({
     u => u.cluster === cluster
   );
 
+  const isReadOnly =
+    alertStore.data.getClusterAlertmanagersWithoutReadOnly(cluster).length ===
+    0;
+
   return (
     <div className="mt-1">
       <div className="d-flex flex-fill flex-lg-row flex-column justify-content-between">
@@ -154,7 +158,8 @@ const SilenceDetails = ({
           <div className="d-flex flex-fill flex-lg-column flex-row justify-content-around">
             <button
               className="btn btn-primary btn-sm mb-lg-2 mb-0"
-              onClick={onEditSilence}
+              disabled={isReadOnly}
+              onClick={!isReadOnly && onEditSilence}
             >
               <FontAwesomeIcon
                 className="mr-1 d-none d-sm-inline-block"
diff --git a/ui/src/Components/ManagedSilence/SilenceDetails.test.js b/ui/src/Components/ManagedSilence/SilenceDetails.test.js
index e5f0cefea..dda44c93a 100644
--- a/ui/src/Components/ManagedSilence/SilenceDetails.test.js
+++ b/ui/src/Components/ManagedSilence/SilenceDetails.test.js
@@ -34,6 +34,7 @@ beforeEach(() => {
         cluster: "am",
         uri: "http://localhost:9093",
         publicURI: "http://example.com",
+        readonly: false,
         error: "",
         version: "0.15.3",
         headers: {}
diff --git a/ui/src/Components/ManagedSilence/index.js b/ui/src/Components/ManagedSilence/index.js
index a5c65f346..43bce27cf 100644
--- a/ui/src/Components/ManagedSilence/index.js
+++ b/ui/src/Components/ManagedSilence/index.js
@@ -47,6 +47,7 @@ const ManagedSilence = observer(
     getAlertmanager = () =>
       this.props.alertStore.data.upstreams.instances
         .filter(u => u.cluster === this.props.cluster)
+        .filter(u => u.readonly === false)
         .slice(0, 1)[0];
 
     onEditSilence = () => {
diff --git a/ui/src/Components/ManagedSilence/index.stories.js b/ui/src/Components/ManagedSilence/index.stories.js
index 225019b47..fdbfb9f7e 100644
--- a/ui/src/Components/ManagedSilence/index.stories.js
+++ b/ui/src/Components/ManagedSilence/index.stories.js
@@ -30,6 +30,7 @@ storiesOf("ManagedSilence", module)
           clusterMembers: ["am1"],
           uri: "http://localhost:9093",
           publicURI: "http://example.com",
+          readonly: false,
           error: "",
           version: "0.15.3",
           headers: {}
@@ -38,6 +39,24 @@ storiesOf("ManagedSilence", module)
       clusters: { am: ["am1"] }
     };
 
+    const alertStoreReadOnly = new AlertStore([]);
+    alertStoreReadOnly.data.upstreams = {
+      clusters: { ro: ["readonly"] },
+      instances: [
+        {
+          name: "readonly",
+          uri: "http://localhost:8080",
+          publicURI: "http://example.com",
+          readonly: true,
+          headers: {},
+          error: "",
+          version: "0.15.0",
+          cluster: "ro",
+          clusterMembers: ["readonly"]
+        }
+      ]
+    };
+
     const silence = MockSilence();
     silence.startsAt = "2018-08-14T16:00:00Z";
     silence.endsAt = "2018-08-14T18:00:00Z";
@@ -67,6 +86,16 @@ storiesOf("ManagedSilence", module)
           onDidUpdate={() => {}}
           isOpen={true}
         />
+        <ManagedSilence
+          cluster={"ro"}
+          alertCount={123}
+          alertCountAlwaysVisible={true}
+          silence={silence}
+          alertStore={alertStoreReadOnly}
+          silenceFormStore={silenceFormStore}
+          onDidUpdate={() => {}}
+          isOpen={true}
+        />
         <ManagedSilence
           cluster={cluster}
           alertCount={123}
@@ -86,6 +115,16 @@ storiesOf("ManagedSilence", module)
           onDidUpdate={() => {}}
           isOpen={true}
         />
+        <ManagedSilence
+          cluster={"ro"}
+          alertCount={123}
+          alertCountAlwaysVisible={true}
+          silence={expiredSilence}
+          alertStore={alertStoreReadOnly}
+          silenceFormStore={silenceFormStore}
+          onDidUpdate={() => {}}
+          isOpen={true}
+        />
       </React.Fragment>
     );
   });
diff --git a/ui/src/Components/ManagedSilence/index.test.js b/ui/src/Components/ManagedSilence/index.test.js
index 63dc58d00..790f0f29e 100644
--- a/ui/src/Components/ManagedSilence/index.test.js
+++ b/ui/src/Components/ManagedSilence/index.test.js
@@ -33,6 +33,7 @@ beforeEach(() => {
         clusterMembers: ["am1"],
         uri: "http://localhost:9093",
         publicURI: "http://example.com",
+        readonly: false,
         error: "",
         version: "0.15.3",
         headers: {}
@@ -95,6 +96,7 @@ describe("<ManagedSilence />", () => {
       clusterMembers: ["am1"],
       uri: "http://localhost:9093",
       publicURI: "http://example.com",
+      readonly: false,
       error: "",
       version: "0.15.3",
       headers: {}
diff --git a/ui/src/Components/SilenceModal/AlertManagerInput/index.js b/ui/src/Components/SilenceModal/AlertManagerInput/index.js
index 0af26a784..145e96dcc 100644
--- a/ui/src/Components/SilenceModal/AlertManagerInput/index.js
+++ b/ui/src/Components/SilenceModal/AlertManagerInput/index.js
@@ -30,7 +30,7 @@ const AlertManagerInput = observer(
 
       if (silenceFormStore.data.alertmanagers.length === 0) {
         silenceFormStore.data.alertmanagers = AlertmanagerClustersToOption(
-          alertStore.data.upstreams.clusters
+          alertStore.data.clustersWithoutReadOnly
         );
       }
     }
@@ -46,7 +46,7 @@ const AlertManagerInput = observer(
 
       // get the list of last known alertmanagers
       const currentAlertmanagers = AlertmanagerClustersToOption(
-        alertStore.data.upstreams.clusters
+        alertStore.data.clustersWithoutReadOnly
       );
 
       // now iterate what's set as silence form values and reset it if any
@@ -75,7 +75,7 @@ const AlertManagerInput = observer(
           instanceId="silence-input-alertmanagers"
           defaultValue={silenceFormStore.data.alertmanagers}
           options={AlertmanagerClustersToOption(
-            alertStore.data.upstreams.clusters
+            alertStore.data.clustersWithoutReadOnly
           )}
           getOptionValue={JSON.stringify}
           placeholder={
diff --git a/ui/src/Components/SilenceModal/AlertManagerInput/index.test.js b/ui/src/Components/SilenceModal/AlertManagerInput/index.test.js
index 21927decb..a6cf97797 100644
--- a/ui/src/Components/SilenceModal/AlertManagerInput/index.test.js
+++ b/ui/src/Components/SilenceModal/AlertManagerInput/index.test.js
@@ -27,6 +27,7 @@ beforeEach(() => {
       name: "am1",
       uri: "http://am1.example.com",
       publicURI: "http://am1.example.com",
+      readonly: false,
       headers: {},
       error: "",
       version: "0.15.0",
@@ -37,6 +38,7 @@ beforeEach(() => {
       name: "am2",
       uri: "http://am2.example.com",
       publicURI: "http://am2.example.com",
+      readonly: false,
       headers: {},
       error: "",
       version: "0.15.0",
@@ -47,6 +49,7 @@ beforeEach(() => {
       name: "am3",
       uri: "http://am3.example.com",
       publicURI: "http://am3.example.com",
+      readonly: false,
       headers: {},
       error: "",
       version: "0.15.0",
@@ -202,4 +205,15 @@ describe("<AlertManagerInput />", () => {
     expect(silenceFormStore.data.alertmanagers).toHaveLength(0);
     expect(silenceFormStore.data.alertmanagers).toEqual([]);
   });
+
+  it("doesn't include readonly instances", () => {
+    alertStore.data.upstreams.instances[0].readonly = true;
+    alertStore.data.upstreams.instances[2].readonly = true;
+    MountedAlertManagerInput();
+    expect(silenceFormStore.data.alertmanagers).toHaveLength(1);
+    expect(silenceFormStore.data.alertmanagers).toContainEqual({
+      label: "am2",
+      value: ["am2"]
+    });
+  });
 });
diff --git a/ui/src/Components/SilenceModal/Browser/index.test.js b/ui/src/Components/SilenceModal/Browser/index.test.js
index 2c0642fdc..006616411 100644
--- a/ui/src/Components/SilenceModal/Browser/index.test.js
+++ b/ui/src/Components/SilenceModal/Browser/index.test.js
@@ -36,6 +36,7 @@ beforeEach(() => {
         clusterMembers: ["am1"],
         uri: "http://localhost:9093",
         publicURI: "http://example.com",
+        readonly: false,
         error: "",
         version: "0.15.3",
         headers: {}
diff --git a/ui/src/Components/SilenceModal/SilenceModalContent.js b/ui/src/Components/SilenceModal/SilenceModalContent.js
index cf7efad8e..fa0c63ef6 100644
--- a/ui/src/Components/SilenceModal/SilenceModalContent.js
+++ b/ui/src/Components/SilenceModal/SilenceModalContent.js
@@ -3,6 +3,9 @@ import PropTypes from "prop-types";
 
 import { observer } from "mobx-react";
 
+import { FontAwesomeIcon } from "@fortawesome/react-fontawesome";
+import { faLock } from "@fortawesome/free-solid-svg-icons/faLock";
+
 import { AlertStore } from "Stores/AlertStore";
 import {
   SilenceFormStore,
@@ -16,6 +19,15 @@ import { SilencePreview } from "./SilencePreview";
 import { SilenceSubmitController } from "./SilenceSubmit/SilenceSubmitController";
 import { Browser } from "./Browser";
 
+const ReadOnlyPlaceholder = () => (
+  <div className="jumbotron bg-transparent">
+    <h1 className="display-5 text-placeholder text-center">
+      <FontAwesomeIcon icon={faLock} className="mr-3" />
+      Read only mode
+    </h1>
+  </div>
+);
+
 const SilenceModalContent = observer(
   class SilenceModalContent extends Component {
     static propTypes = {
@@ -82,12 +94,17 @@ const SilenceModalContent = observer(
             {silenceFormStore.tab.current === SilenceTabNames.Editor ? (
               silenceFormStore.data.currentStage ===
               SilenceFormStage.UserInput ? (
-                <SilenceForm
-                  alertStore={alertStore}
-                  silenceFormStore={silenceFormStore}
-                  settingsStore={settingsStore}
-                  previewOpen={previewOpen}
-                />
+                Object.keys(alertStore.data.clustersWithoutReadOnly).length >
+                0 ? (
+                  <SilenceForm
+                    alertStore={alertStore}
+                    silenceFormStore={silenceFormStore}
+                    settingsStore={settingsStore}
+                    previewOpen={previewOpen}
+                  />
+                ) : (
+                  <ReadOnlyPlaceholder />
+                )
               ) : silenceFormStore.data.currentStage ===
                 SilenceFormStage.Preview ? (
                 <SilencePreview
diff --git a/ui/src/Components/SilenceModal/SilenceModalContent.test.js b/ui/src/Components/SilenceModal/SilenceModalContent.test.js
index 352b54cf1..1c369203c 100644
--- a/ui/src/Components/SilenceModal/SilenceModalContent.test.js
+++ b/ui/src/Components/SilenceModal/SilenceModalContent.test.js
@@ -20,9 +20,28 @@ beforeEach(() => {
   settingsStore = new Settings();
   silenceFormStore = new SilenceFormStore();
 
+  alertStore.data.upstreams = {
+    instances: [
+      {
+        name: "am1",
+        cluster: "am",
+        uri: "http://localhost:9093",
+        readonly: false,
+        error: "",
+        version: "0.15.3",
+        headers: {}
+      }
+    ],
+    clusters: { am: ["am1"] }
+  };
+
   silenceFormStore.tab.current = SilenceTabNames.Editor;
 });
 
+afterEach(() => {
+  jest.restoreAllMocks();
+});
+
 const MockOnHide = jest.fn();
 
 const ShallowSilenceModalContent = () => {
@@ -38,6 +57,13 @@ const ShallowSilenceModalContent = () => {
 };
 
 describe("<SilenceModalContent />", () => {
+  it("Renders ReadOnlyPlaceholder when there are no writable Alertmanager upstreams", () => {
+    alertStore.data.upstreams.instances[0].readonly = true;
+    const tree = ShallowSilenceModalContent();
+    const placeholder = tree.find("ReadOnlyPlaceholder");
+    expect(placeholder).toHaveLength(1);
+  });
+
   it("Clicking on the Browser tab changes content", () => {
     const tree = ShallowSilenceModalContent();
     const tabs = tree.find("Tab");
diff --git a/ui/src/Components/SilenceModal/SilenceSubmit/SilenceSubmitProgress.js b/ui/src/Components/SilenceModal/SilenceSubmit/SilenceSubmitProgress.js
index 56f047992..8e094b666 100644
--- a/ui/src/Components/SilenceModal/SilenceSubmit/SilenceSubmitProgress.js
+++ b/ui/src/Components/SilenceModal/SilenceSubmit/SilenceSubmitProgress.js
@@ -95,9 +95,16 @@ const SilenceSubmitProgress = observer(
 
       const member = this.submitState.membersToTry.pop();
 
+      if (alertStore.data.isReadOnlyAlertmanager(member)) {
+        const err = `Alertmanager instance "${member}" is read-only`;
+        console.error(err);
+        this.maybeTryAgainAfterError(err);
+        return;
+      }
+
       const am = alertStore.data.getAlertmanagerByName(member);
       if (am === undefined) {
-        const err = `Alertmanager instance "${member} not found`;
+        const err = `Alertmanager instance "${member}" not found`;
         console.error(err);
         this.maybeTryAgainAfterError(err);
         return;
diff --git a/ui/src/Components/SilenceModal/SilenceSubmit/SilenceSubmitProgress.test.js b/ui/src/Components/SilenceModal/SilenceSubmit/SilenceSubmitProgress.test.js
index 4fe66a414..8af0ca694 100644
--- a/ui/src/Components/SilenceModal/SilenceSubmit/SilenceSubmitProgress.test.js
+++ b/ui/src/Components/SilenceModal/SilenceSubmit/SilenceSubmitProgress.test.js
@@ -15,6 +15,7 @@ beforeEach(() => {
         name: "mockAlertmanager",
         uri: "http://localhost",
         publicURI: "http://example.com",
+        readonly: false,
         headers: { foo: "bar" },
         error: "",
         version: "0.15.0",
@@ -25,6 +26,10 @@ beforeEach(() => {
   };
 });
 
+afterEach(() => {
+  jest.restoreAllMocks();
+});
+
 const MountedSilenceSubmitProgress = () => {
   return mount(
     <SilenceSubmitProgress
@@ -94,6 +99,7 @@ describe("<SilenceSubmitProgress />", () => {
           name: "am1",
           uri: "http://am1.example.com",
           publicURI: "http://am1.example.com",
+          readonly: false,
           headers: {},
           error: "",
           version: "0.15.0",
@@ -104,6 +110,7 @@ describe("<SilenceSubmitProgress />", () => {
           name: "am2",
           uri: "http://am2.example.com",
           publicURI: "http://am2.example.com",
+          readonly: false,
           headers: {},
           error: "",
           version: "0.15.0",
@@ -150,6 +157,7 @@ describe("<SilenceSubmitProgress />", () => {
           name: "am1",
           uri: "http://am1.example.com",
           publicURI: "http://am1.example.com",
+          readonly: false,
           headers: {},
           error: "",
           version: "0.15.0",
@@ -180,6 +188,66 @@ describe("<SilenceSubmitProgress />", () => {
     expect(consoleSpy).toHaveBeenCalledTimes(1);
   });
 
+  it("will refuse to send requests to an alertmanager instance that is readonly", async () => {
+    fetch.resetMocks();
+    const logs = [];
+    const consoleSpy = jest
+      .spyOn(console, "error")
+      .mockImplementation((message, ...args) => {
+        logs.push(message);
+      });
+
+    alertStore.data.upstreams = {
+      clusters: { ha: ["am1", "am2"] },
+      instances: [
+        {
+          name: "am1",
+          uri: "http://am1.example.com",
+          publicURI: "http://am1.example.com",
+          readonly: false,
+          headers: {},
+          error: "",
+          version: "0.15.0",
+          cluster: "ha",
+          clusterMembers: ["am1", "am2"]
+        },
+        {
+          name: "am2",
+          uri: "http://am2.example.com",
+          publicURI: "http://am2.example.com",
+          readonly: true,
+          headers: {},
+          error: "",
+          version: "0.15.0",
+          cluster: "ha",
+          clusterMembers: ["am1", "am2"]
+        }
+      ]
+    };
+
+    const tree = mount(
+      <SilenceSubmitProgress
+        cluster="ha"
+        members={["am1", "am2"]}
+        payload={{
+          matchers: [],
+          startsAt: "now",
+          endsAt: "later",
+          createdBy: "me@example.com",
+          comment: "fake payload"
+        }}
+        alertStore={alertStore}
+      />
+    );
+    await expect(tree.instance().submitState.fetch).resolves.toBeUndefined();
+    expect(fetch.mock.calls).toHaveLength(1);
+    expect(fetch.mock.calls[0][0]).toBe(
+      "http://am1.example.com/api/v1/silences"
+    );
+    expect(logs).toEqual(['Alertmanager instance "am2" is read-only']);
+    expect(consoleSpy).toHaveBeenCalledTimes(1);
+  });
+
   it("renders returned silence ID on successful fetch", async () => {
     fetch.mockResponseOnce(
       JSON.stringify({ status: "success", data: { silenceId: "123456789" } })
diff --git a/ui/src/Components/SilenceModal/index.stories.js b/ui/src/Components/SilenceModal/index.stories.js
index ca59f129e..7afee41d6 100644
--- a/ui/src/Components/SilenceModal/index.stories.js
+++ b/ui/src/Components/SilenceModal/index.stories.js
@@ -40,6 +40,23 @@ storiesOf("SilenceModal", module)
     const settingsStore = new Settings();
     const silenceFormStore = new SilenceFormStore();
 
+    alertStore.data.upstreams = {
+      clusters: { default: ["default"] },
+      instances: [
+        {
+          name: "default",
+          uri: "http://localhost:8080",
+          publicURI: "http://example.com",
+          readonly: false,
+          headers: {},
+          error: "",
+          version: "0.15.0",
+          cluster: "default",
+          clusterMembers: ["default"]
+        }
+      ]
+    };
+
     silenceFormStore.toggle.visible = true;
     silenceFormStore.data.matchers = [
       MockMatcher("cluster", ["prod"], false),
@@ -96,8 +113,36 @@ storiesOf("SilenceModal", module)
       }
     );
 
+    const alertStoreReadOnly = new AlertStore([]);
+    alertStoreReadOnly.data.upstreams = {
+      clusters: { default: ["readonly"] },
+      instances: [
+        {
+          name: "readonly",
+          uri: "http://localhost:8080",
+          publicURI: "http://example.com",
+          readonly: true,
+          headers: {},
+          error: "",
+          version: "0.15.0",
+          cluster: "default",
+          clusterMembers: ["readonly"]
+        }
+      ]
+    };
+
     return (
       <React.Fragment>
+        <Modal>
+          <SilenceModalContent
+            alertStore={alertStoreReadOnly}
+            silenceFormStore={silenceFormStore}
+            settingsStore={settingsStore}
+            onHide={() => {}}
+            previewOpen={true}
+            onDeleteModalClose={() => {}}
+          />
+        </Modal>
         <Modal>
           <SilenceModalContent
             alertStore={alertStore}
@@ -142,6 +187,7 @@ storiesOf("SilenceModal", module)
           clusterMembers: ["am1"],
           uri: "http://localhost:9093",
           publicURI: "http://example.com",
+          readonly: false,
           error: "",
           version: "0.15.3",
           headers: {}
@@ -204,6 +250,7 @@ storiesOf("SilenceModal", module)
           clusterMembers: ["am1"],
           uri: "http://localhost:9093",
           publicURI: "http://example.com",
+          readonly: false,
           error: "",
           version: "0.15.3",
           headers: {}
diff --git a/ui/src/Models/API.js b/ui/src/Models/API.js
index d55e94782..7f4d5af63 100644
--- a/ui/src/Models/API.js
+++ b/ui/src/Models/API.js
@@ -69,6 +69,7 @@ const APIAlertmanagerUpstream = PropTypes.exact({
   cluster: PropTypes.string.isRequired,
   uri: PropTypes.string.isRequired,
   publicURI: PropTypes.string.isRequired,
+  readonly: PropTypes.bool.isRequired,
   headers: PropTypes.object.isRequired,
   error: PropTypes.string.isRequired,
   version: PropTypes.string.isRequired,
diff --git a/ui/src/Stores/AlertStore.js b/ui/src/Stores/AlertStore.js
index cc2d0bd0b..c31870e58 100644
--- a/ui/src/Stores/AlertStore.js
+++ b/ui/src/Stores/AlertStore.js
@@ -1,4 +1,4 @@
-import { observable, action, toJS } from "mobx";
+import { observable, action, computed, toJS } from "mobx";
 
 import throttle from "lodash/throttle";
 
@@ -167,13 +167,37 @@ class AlertStore {
       getAlertmanagerByName(name) {
         return this.upstreams.instances.find(am => am.name === name);
       },
+      isReadOnlyAlertmanager(name) {
+        return this.readOnlyAlertmanagers.map(am => am.name).includes(name);
+      },
+      getClusterAlertmanagersWithoutReadOnly(clusterID) {
+        return this.clustersWithoutReadOnly[clusterID] || [];
+      },
+      get readOnlyAlertmanagers() {
+        return this.upstreams.instances.filter(am => am.readonly === true);
+      },
+      get clustersWithoutReadOnly() {
+        const clusters = {};
+        for (const clusterID of Object.keys(this.upstreams.clusters)) {
+          const members = this.upstreams.clusters[clusterID].filter(
+            member => this.isReadOnlyAlertmanager(member) === false
+          );
+          if (members.length > 0) {
+            clusters[clusterID] = members;
+          }
+        }
+        return clusters;
+      },
       getColorData(name, value) {
         if (this.colors[name] !== undefined) {
           return this.colors[name][value];
         }
       }
     },
-    {},
+    {
+      readOnlyAlertmanagers: computed,
+      clustersWithoutReadOnly: computed
+    },
     { name: "API Response data" }
   );
 
diff --git a/ui/src/Stores/AlertStore.test.js b/ui/src/Stores/AlertStore.test.js
index 6b95b35d9..98c5e67c7 100644
--- a/ui/src/Stores/AlertStore.test.js
+++ b/ui/src/Stores/AlertStore.test.js
@@ -20,6 +20,78 @@ afterEach(() => {
   delete process.env.REACT_APP_BACKEND_URI;
 });
 
+describe("AlertStore.data", () => {
+  it("getClusterAlertmanagersWithoutReadOnly filters out readonly instances", () => {
+    const store = new AlertStore([]);
+    store.data.upstreams = {
+      clusters: { default: ["default", "readonly"] },
+      instances: [
+        {
+          name: "default",
+          uri: "http://localhost",
+          publicURI: "http://example.com:8080",
+          readonly: false,
+          headers: { foo: "bar" },
+          error: "",
+          version: "0.15.0",
+          cluster: "default",
+          clusterMembers: ["default", "readonly"]
+        },
+        {
+          name: "readonly",
+          uri: "http://localhost:8081",
+          publicURI: "http://example.com",
+          readonly: true,
+          headers: {},
+          error: "",
+          version: "0.15.0",
+          cluster: "default",
+          clusterMembers: ["default", "readonly"]
+        }
+      ]
+    };
+    expect(
+      store.data.getClusterAlertmanagersWithoutReadOnly("default")
+    ).toEqual(["default"]);
+  });
+});
+
+describe("AlertStore.data", () => {
+  it("getClusterAlertmanagersWithoutReadOnly handles clusters with no writable instances", () => {
+    const store = new AlertStore([]);
+    store.data.upstreams = {
+      clusters: { default: ["ro1", "ro2"] },
+      instances: [
+        {
+          name: "ro1",
+          uri: "http://localhost",
+          publicURI: "http://example.com:8080",
+          readonly: true,
+          headers: {},
+          error: "",
+          version: "0.15.0",
+          cluster: "default",
+          clusterMembers: ["ro1", "ro2"]
+        },
+        {
+          name: "ro2",
+          uri: "http://localhost:8081",
+          publicURI: "http://example.com",
+          readonly: true,
+          headers: {},
+          error: "",
+          version: "0.15.0",
+          cluster: "default",
+          clusterMembers: ["ro1", "ro2"]
+        }
+      ]
+    };
+    expect(
+      store.data.getClusterAlertmanagersWithoutReadOnly("default")
+    ).toEqual([]);
+  });
+});
+
 describe("AlertStore.status", () => {
   it("status is initially idle with no error", () => {
     const store = new AlertStore([]);
diff --git a/ui/src/__mocks__/Alerts.js b/ui/src/__mocks__/Alerts.js
index d09fce329..9b6225f18 100644
--- a/ui/src/__mocks__/Alerts.js
+++ b/ui/src/__mocks__/Alerts.js
@@ -70,6 +70,7 @@ const MockAlertmanager = () => ({
   cluster: "default",
   uri: "http://localhost",
   publicURI: "http://am.example.com",
+  readonly: false,
   headers: {
     Authorization: "Basic foo bar"
   },