diff --git a/README.md b/README.md
index cdb7715a5..f15fb8c94 100644
--- a/README.md
+++ b/README.md
@@ -125,6 +125,14 @@ true
 
   The amount of attempts should we make using the current transport to connect to the server? After this we will do one final attempt, and re-try with all enabled transport methods before we give up.
 
+- *'cookie'*
+
+  Any cookies to pass along into the handshake. For example: 
+
+```js
+  io.connect('http://localhost', {'cookie': 'express-sid=aGRKnI4jThJDdWPxEEZIDIGeH5DlA0Fs'});
+```
+  
 ##### Properties:
 
 - *options*
diff --git a/lib/socket.js b/lib/socket.js
index dff44112d..13d5d94c2 100644
--- a/lib/socket.js
+++ b/lib/socket.js
@@ -148,6 +148,9 @@
     } else {
       var xhr = io.util.request();
 
+      if (this.options.cookie) {
+        xhr.setRequestHeader('Cookie', this.options.cookie);
+      }
       xhr.open('GET', url, true);
       xhr.withCredentials = true;
       xhr.onreadystatechange = function () {