diff --git a/README.md b/README.md
index 377dcdd56d..b2149c5cb5 100755
--- a/README.md
+++ b/README.md
@@ -271,6 +271,7 @@ List of Definitions
 * [Underscore.js (Typed)](http://underscorejs.org/) (by [Josh Baldwin](https://github.com/jbaldwin/))
 * [Underscore-ko.js](https://github.com/kamranayub/UnderscoreKO) (by [Maurits Elbers](https://github.com/MagicMau))
 * [universal-analytics](https://github.com/peaksandpies/universal-analytics) (by [Bart van der Schoor](https://github.com/Bartvds))
+* [update-notifier](https://github.com/yeoman/update-notifier) (by [vvakame](https://github.com/vvakame))
 * [urlrouter](https://github.com/fengmk2/urlrouter) (by [Carlos Ballesteros Velasco](https://github.com/soywiz))
 * [UUID.js](https://github.com/LiosK/UUID.js) (by [Jason Jarrett](https://github.com/staxmanade))
 * [Valerie](https://github.com/davewatts/valerie) (by [Howard Richards](https://github.com/conficient))
diff --git a/update-notifier/update-notifier-tests.ts b/update-notifier/update-notifier-tests.ts
new file mode 100644
index 0000000000..58fdbd623e
--- /dev/null
+++ b/update-notifier/update-notifier-tests.ts
@@ -0,0 +1,19 @@
+/// <reference path="./update-notifier.d.ts" />
+
+import updateNotifier = require('update-notifier');
+
+var notifier = updateNotifier();
+
+if (notifier.update) {
+	notifier.notify();
+}
+
+console.log(notifier.update);
+
+var notifier = updateNotifier({
+	updateCheckInterval: 1000 * 60 * 60 * 24 * 7 // 1 week
+});
+
+if (notifier.update) {
+	notifier.notify('Update available: ' + notifier.update.latest);
+}
diff --git a/update-notifier/update-notifier.d.ts b/update-notifier/update-notifier.d.ts
new file mode 100644
index 0000000000..965b3631bf
--- /dev/null
+++ b/update-notifier/update-notifier.d.ts
@@ -0,0 +1,36 @@
+// Type definitions for update-notifier
+// Project: https://github.com/yeoman/update-notifier
+// Definitions by: vvakame <https://github.com/vvakame>
+// Definitions: https://github.com/borisyankov/DefinitelyTyped
+
+declare module "update-notifier" {
+	function t(settings?:t.ISettings):t.IResult;
+
+	module t {
+
+		export interface IResult {
+			update: IUpdateInfo;
+			notify(message?:string):void;
+		}
+
+		export interface ISettings {
+			callback?:(error:any, update?:IUpdateInfo)=>any; // default null
+			packagePath?:string; // default 'package.json'
+			packageName?:string; // default Inferred from packageFile
+			packageVersion?:string; // default Inferred from packageFile
+			updateCheckInterval?:number; // default 1000 * 60 * 60 * 24 (1 day)
+			updateCheckTimeout?:number; // default 20000 (20 secs)
+			registryUrl?:string; // default 'http://registry.npmjs.org/%s'
+		}
+
+		export interface IUpdateInfo {
+			latest:string;
+			current:string;
+			type:string;
+			date:string;
+			name:string;
+		}
+	}
+
+	export = t;
+}