diff --git a/ui/src/Components/MultiSelect/ValidationError.js b/ui/src/Components/MultiSelect/ValidationError.js
new file mode 100644
index 000000000..faf277526
--- /dev/null
+++ b/ui/src/Components/MultiSelect/ValidationError.js
@@ -0,0 +1,12 @@
+import React from "react";
+
+import { FontAwesomeIcon } from "@fortawesome/react-fontawesome";
+import { faExclamationCircle } from "@fortawesome/free-solid-svg-icons/faExclamationCircle";
+
+const ValidationError = () => (
+  <span className="text-danger">
+    <FontAwesomeIcon icon={faExclamationCircle} /> Required
+  </span>
+);
+
+export { ValidationError };
diff --git a/ui/src/Components/MultiSelect/ValidationError.test.js b/ui/src/Components/MultiSelect/ValidationError.test.js
new file mode 100644
index 000000000..cd31b122c
--- /dev/null
+++ b/ui/src/Components/MultiSelect/ValidationError.test.js
@@ -0,0 +1,14 @@
+import React from "react";
+
+import { shallow } from "enzyme";
+
+import toDiffableHtml from "diffable-html";
+
+import { ValidationError } from "./ValidationError";
+
+describe("<ValidationError />", () => {
+  it("matches snapshot", () => {
+    const tree = shallow(<ValidationError />);
+    expect(toDiffableHtml(tree.html())).toMatchSnapshot();
+  });
+});
diff --git a/ui/src/Components/MultiSelect/__snapshots__/ValidationError.test.js.snap b/ui/src/Components/MultiSelect/__snapshots__/ValidationError.test.js.snap
new file mode 100644
index 000000000..bddec3114
--- /dev/null
+++ b/ui/src/Components/MultiSelect/__snapshots__/ValidationError.test.js.snap
@@ -0,0 +1,22 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`<ValidationError /> matches snapshot 1`] = `
+"
+<span class=\\"text-danger\\">
+  <svg aria-hidden=\\"true\\"
+       data-prefix=\\"fas\\"
+       data-icon=\\"exclamation-circle\\"
+       class=\\"svg-inline--fa fa-exclamation-circle fa-w-16 \\"
+       role=\\"img\\"
+       xmlns=\\"http://www.w3.org/2000/svg\\"
+       viewbox=\\"0 0 512 512\\"
+  >
+    <path fill=\\"currentColor\\"
+          d=\\"M504 256c0 136.997-111.043 248-248 248S8 392.997 8 256C8 119.083 119.043 8 256 8s248 111.083 248 248zm-248 50c-25.405 0-46 20.595-46 46s20.595 46 46 46 46-20.595 46-46-20.595-46-46-46zm-43.673-165.346l7.418 136c.347 6.364 5.609 11.346 11.982 11.346h48.546c6.373 0 11.635-4.982 11.982-11.346l7.418-136c.375-6.874-5.098-12.654-11.982-12.654h-63.383c-6.884 0-12.356 5.78-11.981 12.654z\\"
+    >
+    </path>
+  </svg>
+  Required
+</span>
+"
+`;
diff --git a/ui/src/Components/SilenceModal/AlertManagerInput.js b/ui/src/Components/SilenceModal/AlertManagerInput.js
index 816218569..134d5f743 100644
--- a/ui/src/Components/SilenceModal/AlertManagerInput.js
+++ b/ui/src/Components/SilenceModal/AlertManagerInput.js
@@ -7,6 +7,7 @@ import { observer } from "mobx-react";
 import ReactSelect from "react-select";
 
 import { MultiSelect, ReactSelectStyles } from "Components/MultiSelect";
+import { ValidationError } from "Components/MultiSelect/ValidationError";
 
 const AlertmanagerInstancesToOptions = instances =>
   instances.map(i => ({
@@ -75,7 +76,13 @@ const AlertManagerInput = observer(
           options={AlertmanagerInstancesToOptions(
             alertStore.data.upstreams.instances
           )}
-          placeholder="Alertmanager"
+          placeholder={
+            silenceFormStore.data.wasValidated ? (
+              <ValidationError />
+            ) : (
+              "Alertmanager"
+            )
+          }
           isMulti
           onChange={this.onChange}
         />
diff --git a/ui/src/Components/SilenceModal/AlertManagerInput.test.js b/ui/src/Components/SilenceModal/AlertManagerInput.test.js
index 75c42bb1b..ca863bbf9 100644
--- a/ui/src/Components/SilenceModal/AlertManagerInput.test.js
+++ b/ui/src/Components/SilenceModal/AlertManagerInput.test.js
@@ -60,6 +60,21 @@ describe("<AlertManagerInput />", () => {
     expect(tree).toMatchSnapshot();
   });
 
+  it("doesn't render ValidationError after passed validation", () => {
+    const tree = ShallowAlertManagerInput();
+    silenceFormStore.data.wasValidated = true;
+    expect(tree.html()).not.toMatch(/fa-exclamation-circle/);
+    expect(tree.html()).not.toMatch(/Required/);
+  });
+
+  it("renders ValidationError after failed validation", () => {
+    const tree = ShallowAlertManagerInput();
+    silenceFormStore.data.alertmanagers = [];
+    silenceFormStore.data.wasValidated = true;
+    expect(tree.html()).toMatch(/fa-exclamation-circle/);
+    expect(tree.html()).toMatch(/Required/);
+  });
+
   it("all available Alertmanager instances are selected by default", () => {
     ShallowAlertManagerInput();
     expect(silenceFormStore.data.alertmanagers).toHaveLength(3);
diff --git a/ui/src/Components/SilenceModal/LabelNameInput.js b/ui/src/Components/SilenceModal/LabelNameInput.js
index 643825d1a..cb55c1a30 100644
--- a/ui/src/Components/SilenceModal/LabelNameInput.js
+++ b/ui/src/Components/SilenceModal/LabelNameInput.js
@@ -1,15 +1,18 @@
+import React from "react";
 import PropTypes from "prop-types";
 
 import { action } from "mobx";
 import { observer } from "mobx-react";
 
 import { MultiSelect } from "Components/MultiSelect";
+import { ValidationError } from "Components/MultiSelect/ValidationError";
 import { FormatUnseeBackendURI } from "Stores/AlertStore";
 
 const LabelNameInput = observer(
   class LabelNameInput extends MultiSelect {
     static propTypes = {
-      matcher: PropTypes.object.isRequired
+      matcher: PropTypes.object.isRequired,
+      isValid: PropTypes.bool.isRequired
     };
 
     populateNameSuggestions = action(() => {
@@ -70,7 +73,7 @@ const LabelNameInput = observer(
     }
 
     renderProps = () => {
-      const { matcher } = this.props;
+      const { matcher, isValid } = this.props;
 
       const value = matcher.name
         ? { label: matcher.name, value: matcher.name }
@@ -80,7 +83,7 @@ const LabelNameInput = observer(
         instanceId: `silence-input-label-name-${matcher.id}`,
         defaultValue: value,
         options: matcher.suggestions.names,
-        placeholder: "Label name",
+        placeholder: isValid ? "Label name" : <ValidationError />,
         onChange: this.onChange
       };
     };
diff --git a/ui/src/Components/SilenceModal/LabelNameInput.test.js b/ui/src/Components/SilenceModal/LabelNameInput.test.js
index 6af967fd4..221323357 100644
--- a/ui/src/Components/SilenceModal/LabelNameInput.test.js
+++ b/ui/src/Components/SilenceModal/LabelNameInput.test.js
@@ -20,16 +20,16 @@ beforeEach(() => {
   ];
 });
 
-const ShallowLabelNameInput = () => {
-  return shallow(<LabelNameInput matcher={matcher} />);
+const ShallowLabelNameInput = isValid => {
+  return shallow(<LabelNameInput matcher={matcher} isValid={isValid} />);
 };
 
-const MountedLabelNameInput = () => {
-  return mount(<LabelNameInput matcher={matcher} />);
+const MountedLabelNameInput = isValid => {
+  return mount(<LabelNameInput matcher={matcher} isValid={isValid} />);
 };
 
 const ValidateSuggestions = () => {
-  const tree = MountedLabelNameInput();
+  const tree = MountedLabelNameInput(true);
   // click on the react-select component doesn't seem to trigger options
   // rendering in tests, so change the input instead
   tree.find("input").simulate("change", { target: { value: "f" } });
@@ -38,10 +38,28 @@ const ValidateSuggestions = () => {
 
 describe("<LabelNameInput />", () => {
   it("matches snapshot", () => {
-    const tree = ShallowLabelNameInput();
+    const tree = ShallowLabelNameInput(true);
     expect(tree).toMatchSnapshot();
   });
 
+  it("doesn't renders ValidationError after passed validation", () => {
+    // clear the name so placeholder is rendered
+    matcher.name = "";
+    const tree = ShallowLabelNameInput(true);
+    expect(tree.html()).toMatch(/Label name/);
+    expect(tree.html()).not.toMatch(/fa-exclamation-circle/);
+    expect(tree.html()).not.toMatch(/Required/);
+  });
+
+  it("renders ValidationError after failed validation", () => {
+    // clear the name so placeholder is rendered
+    matcher.name = "";
+    const tree = ShallowLabelNameInput(false);
+    expect(tree.html()).not.toMatch(/Label name/);
+    expect(tree.html()).toMatch(/fa-exclamation-circle/);
+    expect(tree.html()).toMatch(/Required/);
+  });
+
   it("renders suggestions", () => {
     const tree = ValidateSuggestions();
     const options = tree.find("[role='option']");
@@ -61,7 +79,7 @@ describe("<LabelNameInput />", () => {
     fetch
       .once(JSON.stringify(["name1", "name2", "name3"]))
       .once(JSON.stringify(["value1", "value2", "value3"]));
-    ShallowLabelNameInput();
+    ShallowLabelNameInput(true);
     // use timeout since mount will call fetch
     setTimeout(() => {
       expect(matcher.suggestions.names).toHaveLength(3);
@@ -79,7 +97,7 @@ describe("<LabelNameInput />", () => {
 
   it("suggestions are emptied on failed fetch", done => {
     fetch.mockReject(new Error("fake error message"));
-    ShallowLabelNameInput();
+    ShallowLabelNameInput(true);
     // use timeout since mount will call fetch
     setTimeout(() => {
       expect(matcher.suggestions.names).toHaveLength(0);
@@ -88,7 +106,7 @@ describe("<LabelNameInput />", () => {
   });
 
   it("doesn't fetch suggestions if value is changed to empty string", () => {
-    const tree = MountedLabelNameInput();
+    const tree = MountedLabelNameInput(true);
     const instance = tree.instance();
     const fetchSpy = jest.spyOn(instance, "populateValueSuggestions");
     instance.onChange("");
diff --git a/ui/src/Components/SilenceModal/LabelValueInput.js b/ui/src/Components/SilenceModal/LabelValueInput.js
index f3eb989a2..4eb2e762c 100644
--- a/ui/src/Components/SilenceModal/LabelValueInput.js
+++ b/ui/src/Components/SilenceModal/LabelValueInput.js
@@ -1,14 +1,17 @@
+import React from "react";
 import PropTypes from "prop-types";
 
 import { action } from "mobx";
 import { observer } from "mobx-react";
 
 import { MultiSelect } from "Components/MultiSelect";
+import { ValidationError } from "Components/MultiSelect/ValidationError";
 
 const LabelValueInput = observer(
   class LabelValueInput extends MultiSelect {
     static propTypes = {
-      matcher: PropTypes.object.isRequired
+      matcher: PropTypes.object.isRequired,
+      isValid: PropTypes.bool.isRequired
     };
 
     onChange = action((newValue, actionMeta) => {
@@ -25,13 +28,13 @@ const LabelValueInput = observer(
     });
 
     renderProps = () => {
-      const { matcher } = this.props;
+      const { matcher, isValid } = this.props;
 
       return {
         instanceId: `silence-input-label-value-${matcher.id}`,
         defaultValue: matcher.values,
         options: matcher.suggestions.values,
-        placeholder: "Label value",
+        placeholder: isValid ? "Label value" : <ValidationError />,
         isMulti: true,
         onChange: this.onChange
       };
diff --git a/ui/src/Components/SilenceModal/LabelValueInput.test.js b/ui/src/Components/SilenceModal/LabelValueInput.test.js
index 2fc487d2d..c4699c357 100644
--- a/ui/src/Components/SilenceModal/LabelValueInput.test.js
+++ b/ui/src/Components/SilenceModal/LabelValueInput.test.js
@@ -20,16 +20,16 @@ beforeEach(() => {
   ];
 });
 
-const ShallowLabelValueInput = () => {
-  return shallow(<LabelValueInput matcher={matcher} />);
+const ShallowLabelValueInput = isValid => {
+  return shallow(<LabelValueInput matcher={matcher} isValid={isValid} />);
 };
 
-const MountedLabelValueInput = () => {
-  return mount(<LabelValueInput matcher={matcher} />);
+const MountedLabelValueInput = isValid => {
+  return mount(<LabelValueInput matcher={matcher} isValid={isValid} />);
 };
 
 const ValidateSuggestions = () => {
-  const tree = MountedLabelValueInput();
+  const tree = MountedLabelValueInput(true);
   // click on the react-select component doesn't seem to trigger options
   // rendering in tests, so change the input instead
   tree.find("input").simulate("change", { target: { value: "f" } });
@@ -38,10 +38,22 @@ const ValidateSuggestions = () => {
 
 describe("<LabelValueInput />", () => {
   it("matches snapshot", () => {
-    const tree = ShallowLabelValueInput();
+    const tree = ShallowLabelValueInput(true);
     expect(tree).toMatchSnapshot();
   });
 
+  it("doesn't renders ValidationError after passed validation", () => {
+    const tree = ShallowLabelValueInput(true);
+    expect(tree.html()).not.toMatch(/fa-exclamation-circle/);
+    expect(tree.html()).not.toMatch(/Required/);
+  });
+
+  it("renders ValidationError after failed validation", () => {
+    const tree = ShallowLabelValueInput(false);
+    expect(tree.html()).toMatch(/fa-exclamation-circle/);
+    expect(tree.html()).toMatch(/Required/);
+  });
+
   it("renders suggestions", () => {
     const tree = ValidateSuggestions();
     const options = tree.find("[role='option']");
diff --git a/ui/src/Components/SilenceModal/SilenceForm.js b/ui/src/Components/SilenceModal/SilenceForm.js
index 7215d62e4..1526a9523 100644
--- a/ui/src/Components/SilenceModal/SilenceForm.js
+++ b/ui/src/Components/SilenceModal/SilenceForm.js
@@ -104,6 +104,8 @@ const SilenceForm = observer(
 
       if (silenceFormStore.data.isValid)
         silenceFormStore.data.inProgress = true;
+
+      silenceFormStore.data.wasValidated = true;
     });
 
     render() {
@@ -125,6 +127,7 @@ const SilenceForm = observer(
                 silenceFormStore.data.deleteMatcher(matcher.id);
               }}
               showDelete={silenceFormStore.data.matchers.length > 1}
+              isValid={!silenceFormStore.data.wasValidated}
             />
           ))}
           <button
diff --git a/ui/src/Components/SilenceModal/SilenceMatch.js b/ui/src/Components/SilenceModal/SilenceMatch.js
index ddeb67328..5172e2fb4 100644
--- a/ui/src/Components/SilenceModal/SilenceMatch.js
+++ b/ui/src/Components/SilenceModal/SilenceMatch.js
@@ -20,7 +20,8 @@ const SilenceMatch = observer(
         isRegex: PropTypes.bool.isRequired
       }),
       showDelete: PropTypes.bool.isRequired,
-      onDelete: PropTypes.func.isRequired
+      onDelete: PropTypes.func.isRequired,
+      isValid: PropTypes.bool.isRequired
     };
 
     onIsRegexChange = action(event => {
@@ -33,15 +34,15 @@ const SilenceMatch = observer(
     });
 
     render() {
-      const { matcher, showDelete, onDelete } = this.props;
+      const { matcher, showDelete, onDelete, isValid } = this.props;
 
       return (
         <div className="d-flex flex-fill flex-lg-row flex-column mb-3">
           <div className="flex-shrink-0 flex-grow-0 flex-basis-25 pr-lg-2 pb-2 pb-lg-0">
-            <LabelNameInput matcher={matcher} />
+            <LabelNameInput matcher={matcher} isValid={isValid} />
           </div>
           <div className="flex-shrink-0 flex-grow-0 flex-basis-50 pr-lg-2 pb-2 pb-lg-0">
-            <LabelValueInput matcher={matcher} />
+            <LabelValueInput matcher={matcher} isValid={isValid} />
           </div>
           <div className="flex-shrink-0 flex-grow-1 flex-basis-auto form-check form-check-inline d-flex justify-content-between m-0">
             <span>
diff --git a/ui/src/Components/SilenceModal/SilenceMatch.test.js b/ui/src/Components/SilenceModal/SilenceMatch.test.js
index 5a8ebb9c9..958a80adc 100644
--- a/ui/src/Components/SilenceModal/SilenceMatch.test.js
+++ b/ui/src/Components/SilenceModal/SilenceMatch.test.js
@@ -2,17 +2,25 @@ import React from "react";
 
 import { shallow } from "enzyme";
 
-import { NewEmptyMatcher, MatcherValueToObject } from "Stores/SilenceFormStore";
+import {
+  SilenceFormStore,
+  NewEmptyMatcher,
+  MatcherValueToObject
+} from "Stores/SilenceFormStore";
 import { SilenceMatch } from "./SilenceMatch";
 
+let silenceFormStore;
 let matcher;
 
 beforeEach(() => {
+  silenceFormStore = new SilenceFormStore();
   matcher = NewEmptyMatcher();
 });
 
 const ShallowLabelValueInput = () => {
-  return shallow(<SilenceMatch matcher={matcher} />);
+  return shallow(
+    <SilenceMatch matcher={matcher} silenceFormStore={silenceFormStore} />
+  );
 };
 
 describe("<SilenceMatch />", () => {
diff --git a/ui/src/Stores/SilenceFormStore.js b/ui/src/Stores/SilenceFormStore.js
index 0d42ac3b6..600d0bce1 100644
--- a/ui/src/Stores/SilenceFormStore.js
+++ b/ui/src/Stores/SilenceFormStore.js
@@ -44,6 +44,7 @@ class SilenceFormStore {
   data = observable(
     {
       inProgress: false,
+      wasValidated: false,
       alertmanagers: [],
       matchers: [],
       startsAt: moment(),
@@ -70,6 +71,7 @@ class SilenceFormStore {
 
       resetProgress() {
         this.inProgress = false;
+        this.wasValidated = false;
       },
 
       // append a new empty matcher to the list
diff --git a/ui/src/Stores/SilenceFormStore.test.js b/ui/src/Stores/SilenceFormStore.test.js
index ea690a1d9..6d8e13c32 100644
--- a/ui/src/Stores/SilenceFormStore.test.js
+++ b/ui/src/Stores/SilenceFormStore.test.js
@@ -52,6 +52,13 @@ describe("SilenceFormStore.data", () => {
     expect(store.data.inProgress).toBe(false);
   });
 
+  it("resetProgress() sets 'wasValidated' to false", () => {
+    store.data.wasValidated = true;
+    expect(store.data.wasValidated).toBe(true);
+    store.data.resetProgress();
+    expect(store.data.wasValidated).toBe(false);
+  });
+
   it("addEmptyMatcher() appends a matcher", () => {
     expect(store.data.matchers).toHaveLength(0);
     store.data.addEmptyMatcher();