diff --git a/deep-extend/deep-extend-tests.ts b/deep-extend/deep-extend-tests.ts
new file mode 100644
index 0000000000..f5e35af352
--- /dev/null
+++ b/deep-extend/deep-extend-tests.ts
@@ -0,0 +1,36 @@
+/// <reference path="deep-extend.d.ts" />
+
+import deepExtend = require('deep-extend');
+var obj1 = {
+  a: 1,
+  b: 2,
+  d: {
+    a: 1,
+    b: [true],
+    c: { test1: 123, test2: 321 }
+  },
+  f: 5,
+  g: 123,
+  i: 321,
+  j: [1, 2]
+};
+var obj2 = {
+  b: 3,
+  c: 5,
+  d: {
+    b: { first: 'one', second: 'two' },
+    c: { test2: 222 }
+  },
+  e: { one: 1, two: 2 },
+  f: [42],
+  g: function(){},
+  h: /abc/g,
+  i: null as {aaa: boolean},
+  j: [3, 4]
+};
+
+deepExtend(obj1, obj2);
+deepExtend(obj1, obj2, {ccc: 3});
+deepExtend(obj1, obj2, {ccc: 3}, {ddd: 4});
+
+
diff --git a/deep-extend/deep-extend.d.ts b/deep-extend/deep-extend.d.ts
new file mode 100644
index 0000000000..164e337a95
--- /dev/null
+++ b/deep-extend/deep-extend.d.ts
@@ -0,0 +1,15 @@
+// Type definitions for open 0.4.1
+// Project: https://github.com/unclechu/node-deep-extend
+// Definitions by: rhysd <https://github.com/rhysd>
+// Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
+
+declare module 'deep-extend' {
+	/*
+	 * Recursive object extending.
+	 */
+	function deepExtend<T, U>(target: T, source: U): T & U;
+	function deepExtend<T, U, V>(target: T, source1: U, source2: V): T & U & V;
+	function deepExtend<T, U, V, W>(target: T, source1: U, source2: V, source3: W): T & U & V & W;
+	function deepExtend(target: any, ...sources: any[]): any;
+	export = deepExtend;
+}