os.diff

diff --git a/lib/os.js b/lib/os.js
index 279b635..e568e8f 100644
--- a/lib/os.js
+++ b/lib/os.js
@@ -44,8 +44,9 @@ exports.platform = function() {
 
 exports.tmpdir = function() {
   if (isWindows) {
-    return process.env.TEMP ||
+    return process.env.TMPDIR ||
            process.env.TMP ||
+           process.env.TEMP ||
            (process.env.SystemRoot || process.env.windir) + "\\temp";
   } else {
     return process.env.TMPDIR ||
diff --git a/test/simple/test-os.js b/test/simple/test-os.js
index 79de1b1..b08e5fc 100644
--- a/test/simple/test-os.js
+++ b/test/simple/test-os.js
@@ -30,7 +30,9 @@ var os = require('os');
 process.env.TMPDIR = '/tmpdir';
 process.env.TMP = '/tmp';
 process.env.TEMP = '/temp';
-var t = ( process.platform === 'win32' ? 'c:\\windows\\temp' : '/tmp' );
+var t = 'tmp';
+if (process.platform === 'win32')
+  t = (process.env.SystemRoot || process.env.windir) + "\\temp";
 assert.equal(os.tmpdir(), '/tmpdir');
 process.env.TMPDIR = '';
 assert.equal(os.tmpdir(), '/tmp')