diff --git a/types/angular-material/angular-material-tests.ts b/types/angular-material/angular-material-tests.ts
index ce5a9bf71e..ac4a1386cd 100644
--- a/types/angular-material/angular-material-tests.ts
+++ b/types/angular-material/angular-material-tests.ts
@@ -140,6 +140,9 @@ myApp.controller('DialogController', ($scope: TestScope, $mdDialog: ng.material.
     $scope['promptDialog'] = () => {
         $mdDialog.show($mdDialog.prompt().initialValue('Buddy'));
     };
+    $scope['promptDialog'] = () => {
+        $mdDialog.show($mdDialog.prompt().required(true));
+    };
     $scope['prerenderedDialog'] = () => {
         $mdDialog.show({
             template: '<md-dialog>Hello!</md-dialog>',
diff --git a/types/angular-material/index.d.ts b/types/angular-material/index.d.ts
index 2dca0c66da..92f6d46751 100644
--- a/types/angular-material/index.d.ts
+++ b/types/angular-material/index.d.ts
@@ -80,6 +80,7 @@ declare module 'angular' {
 
         interface IPromptDialog extends IPresetDialog<IPromptDialog> {
             cancel(cancel: string): IPromptDialog;
+            required(required: boolean): IPromptDialog; // default: false
             placeholder(placeholder: string): IPromptDialog;
             initialValue(initialValue: string): IPromptDialog;
         }