diff --git a/gridfs-stream/gridfs-stream.d.ts b/gridfs-stream/gridfs-stream.d.ts
new file mode 100644
index 0000000000..11bc3adb20
--- /dev/null
+++ b/gridfs-stream/gridfs-stream.d.ts
@@ -0,0 +1,66 @@
+// Type definitions for gridfs-stream 0.5.0
+// Project: https://github.com/aheckmann/gridfs-stream
+// Definitions by: Lior Mualem <https://github.com/liorm/>
+
+/* =================== USAGE ===================
+
+ import express = require('express');
+ var app = express();
+
+ =============================================== */
+
+/// <reference path="../node/node.d.ts" />
+/// <reference path="../mongodb/mongodb.d.ts" />
+
+declare module GridFSStream {
+    export interface Range {
+        startPos: number;
+        endPos: number;
+    }
+
+    export interface Options {
+        _id?: string;
+        filename?: string;
+        mode?: string;
+
+        range?: Range;
+
+        // any other options from the GridStore may be passed too, e.g.
+        chunkSize?: number;
+        content_type?: string;
+        root?: string;
+        metadata?: any;
+    }
+
+    export interface WriteStream extends NodeJS.WritableStream {
+    }
+
+    export interface ReadStream extends NodeJS.ReadableStream {
+    }
+}
+
+declare module "gridfs-stream" {
+    import mongo = require('mongodb');
+
+    // Merged declaration, g is both a callable function and a namespace
+    function g(db: any, mongo: any): g.Grid;
+
+    module g {
+
+        export class Grid {
+            files: mongo.Collection;
+            collection: mongo.Collection;
+
+            createWriteStream(options?: GridFSStream.Options) : GridFSStream.WriteStream;
+            createReadStream(options?: GridFSStream.Options) : GridFSStream.ReadStream;
+            createWriteStream(options?: string) : GridFSStream.WriteStream;
+            createReadStream(options?: string) : GridFSStream.ReadStream;
+
+            remove(options: GridFSStream.Options, callback: (err: Error) => void);
+            exist(options: GridFSStream.Options, callback: (err: Error, found: boolean) => void);
+        }
+    }
+
+    export = g;
+}
+