diff --git a/CONTRIBUTORS.md b/CONTRIBUTORS.md
index fda65cb32..97d34f447 100644
--- a/CONTRIBUTORS.md
+++ b/CONTRIBUTORS.md
@@ -243,7 +243,8 @@ All definitions files include a header with the author and editors, so at some p
 * [Marked](https://github.com/chjj/marked) (by [William Orr](https://github.com/worr))
 * [MathJax](https://github.com/mathjax/MathJax) (by [Roland Zwaga](https://github.com/rolandzwaga))
 * [mCustomScrollbar](https://github.com/malihu/malihu-custom-scrollbar-plugin) (by [Sarah Williams](https://github.com/flurg))
-* [Meteor](https://www.meteor.com) (by [Dave Allen](https://github.com/fullflavedave))
+* [Meteor](https://www.meteor.com) (by [Dave Allen](https://github.com/fullflavedave))
+* [md5.js](http://labs.cybozu.co.jp/blog/mitsunari/2007/07/md5js_1.html) (by [MIZUNE Pine](https://github.com/pine613))
 * [Microsoft Ajax](http://msdn.microsoft.com/en-us/library/ee341002(v=vs.100).aspx) (by [Patrick Magee](https://github.com/pjmagee))
 * [Microsoft Live Connect](http://msdn.microsoft.com/en-us/library/live/hh243643.aspx) (by [John Vilk](https://github.com/jvilk))
 * [Minimatch](https://github.com/isaacs/minimatch) (by [vvakame](https://github.com/vvakame))
diff --git a/md5/md5-test.ts b/md5/md5-test.ts
new file mode 100644
index 000000000..036ad9c2a
--- /dev/null
+++ b/md5/md5-test.ts
@@ -0,0 +1,9 @@
+/// <reference path="md5.d.ts" />
+
+var hash: string;
+hash = CybozuLabs.MD5.calc("abc");
+hash = CybozuLabs.MD5.calc("abc", CybozuLabs.MD5.BY_ASCII);
+hash = CybozuLabs.MD5.calc("abc", CybozuLabs.MD5.BY_UTF16);
+
+var version: string;
+version = CybozuLabs.MD5.VERSION;
\ No newline at end of file
diff --git a/md5/md5.d.ts b/md5/md5.d.ts
new file mode 100644
index 000000000..207a30699
--- /dev/null
+++ b/md5/md5.d.ts
@@ -0,0 +1,11 @@
+// Type definitions for CybozuLabs.MD5
+// Project: http://labs.cybozu.co.jp/blog/mitsunari/2007/07/md5js_1.html
+// Definitions by: MIZUNE Pine <https://github.com/pine613>
+// Definitions: https://github.com/borisyankov/DefinitelyTyped
+
+declare module CybozuLabs.MD5 {
+    var VERSION: string;
+    var BY_ASCII: number;
+    var BY_UTF16: number;
+    function calc(str: string, option?: number): string;
+}
\ No newline at end of file