diff --git a/node/node-tests.ts b/node/node-tests.ts
index 930bd1a71e..4ca651b333 100644
--- a/node/node-tests.ts
+++ b/node/node-tests.ts
@@ -14,6 +14,7 @@ import * as querystring from "querystring";
 import * as path from "path";
 import * as readline from "readline";
 import * as childProcess from "child_process";
+import * as os from "os";
 
 assert(1 + 1 - 2 === 0, "The universe isn't how it should.");
 
@@ -411,3 +412,49 @@ rl.question("do you like typescript?", function(answer: string) {
 
 childProcess.exec("echo test");
 childProcess.spawnSync("echo test");
+
+////////////////////////////////////////////////////
+/// os tests : https://nodejs.org/api/os.html
+////////////////////////////////////////////////////
+
+module os_tests {
+    {
+        let result: string;
+
+        result = os.tmpdir();
+        result = os.homedir();
+        result = os.endianness();
+        result = os.hostname();
+        result = os.type();
+        result = os.platform();
+        result = os.arch();
+        result = os.release();
+        result = os.EOL;
+    }
+
+    {
+        let result: number;
+
+        result = os.uptime();
+        result = os.totalmem();
+        result = os.freemem();
+    }
+
+    {
+        let result: number[];
+
+        result = os.loadavg();
+    }
+
+    {
+        let result: os.CpuInfo[];
+
+        result = os.cpus();
+    }
+
+    {
+        let result: {[index: string]: os.NetworkInterfaceInfo[]};
+
+        result = os.networkInterfaces();
+    }
+}
diff --git a/node/node.d.ts b/node/node.d.ts
index 017ca8e6b9..39be040a49 100644
--- a/node/node.d.ts
+++ b/node/node.d.ts
@@ -698,7 +698,29 @@ declare module "zlib" {
 }
 
 declare module "os" {
+    export interface CpuInfo {
+        model: string;
+        speed: number;
+        times: {
+            user: number;
+            nice: number;
+            sys: number;
+            idle: number;
+            irq: number;
+        }
+    }
+
+    export interface NetworkInterfaceInfo {
+        address: string;
+        netmask: string;
+        family: string;
+        mac: string;
+        internal: boolean;
+    }
+
     export function tmpdir(): string;
+    export function homedir(): string;
+    export function endianness(): string;
     export function hostname(): string;
     export function type(): string;
     export function platform(): string;
@@ -708,8 +730,8 @@ declare module "os" {
     export function loadavg(): number[];
     export function totalmem(): number;
     export function freemem(): number;
-    export function cpus(): { model: string; speed: number; times: { user: number; nice: number; sys: number; idle: number; irq: number; }; }[];
-    export function networkInterfaces(): any;
+    export function cpus(): CpuInfo[];
+    export function networkInterfaces(): {[index: string]: NetworkInterfaceInfo[]};
     export var EOL: string;
 }