diff --git a/protobufjs/protobufjs-tests.ts b/protobufjs/protobufjs-tests.ts
new file mode 100644
index 000000000..148eb05e3
--- /dev/null
+++ b/protobufjs/protobufjs-tests.ts
@@ -0,0 +1,11 @@
+/// <reference path="protobufjs.d.ts" />
+
+import ProtoBuf = require("protobufjs");
+
+ProtoBuf.loadProtoFile("test.proto", builder => {
+	builder.build();
+
+	var message: ProtoBuf.IProtoBufMessage;
+	message.toArrayBuffer();
+	message.toBuffer();
+});
diff --git a/protobufjs/protobufjs.d.ts b/protobufjs/protobufjs.d.ts
new file mode 100644
index 000000000..66a48dc78
--- /dev/null
+++ b/protobufjs/protobufjs.d.ts
@@ -0,0 +1,23 @@
+// Type definitions for ProtoBuf.js
+// Project: https://github.com/dcodeIO/ProtoBuf.js
+// Definitions by: Panu Horsmalahti <https://github.com/panuhorsmalahti>
+// Definitions: https://github.com/borisyankov/DefinitelyTyped
+
+/// <reference path="../node/node.d.ts" />
+
+declare module ProtoBuf {
+	export interface IBuilder {
+		build: <T>() => T;
+	}
+
+	export interface IProtoBufMessage {
+	    toArrayBuffer(): ArrayBuffer;
+	    toBuffer(): Buffer;
+	}
+
+	export function loadProtoFile(filePath: string, callback: (builder: IBuilder) => void): any;
+}
+
+declare module "protobufjs" {
+    export = ProtoBuf;
+}