diff --git a/README.md b/README.md
index 39ce2d6..bab32e2 100644
--- a/README.md
+++ b/README.md
@@ -36,6 +36,15 @@ socket.on(Socket.EVENT_ERROR, new Emitter.Listener() {
 });
 ```
 
+How to set options:
+
+```java
+opts = new Socket.Options();
+opts.cookie = "foo=1;"
+
+socket = new Socket("ws://localhost", opts) { ... };
+```
+
 See the Javadoc for more details.
 
 http://nkzawa.github.io/engine.io-client.java/apidocs/
diff --git a/src/main/java/com/github/nkzawa/engineio/client/Socket.java b/src/main/java/com/github/nkzawa/engineio/client/Socket.java
index 79507d1..3a5440b 100644
--- a/src/main/java/com/github/nkzawa/engineio/client/Socket.java
+++ b/src/main/java/com/github/nkzawa/engineio/client/Socket.java
@@ -102,6 +102,7 @@ public abstract class Socket extends Emitter {
     private String hostname;
     private String path;
     private String timestampParam;
+    private String cookie;
     private List<String> transports;
     private List<String> upgrades;
     private Map<String, String> query;
@@ -165,6 +166,7 @@ public abstract class Socket extends Emitter {
         this.transports = new ArrayList<String>(Arrays.asList(opts.transports != null ?
                 opts.transports : new String[]{Polling.NAME, WebSocket.NAME}));
         this.policyPort = opts.policyPort != 0 ? opts.policyPort : 843;
+        this.cookie = opts.cookie;
 
         Socket.sockets.add(this);
         Socket.sockets.evs.emit(Sockets.EVENT_ADD, this);
@@ -204,6 +206,7 @@ public abstract class Socket extends Emitter {
         opts.timestampRequests = this.timestampRequests;
         opts.timestampParam = this.timestampParam;
         opts.policyPort = this.policyPort;
+        opts.cookie = this.cookie;
 
         if (WebSocket.NAME.equals(name)) {
             return new WebSocket(opts);
diff --git a/src/main/java/com/github/nkzawa/engineio/client/Transport.java b/src/main/java/com/github/nkzawa/engineio/client/Transport.java
index 5102c5a..5a61b53 100644
--- a/src/main/java/com/github/nkzawa/engineio/client/Transport.java
+++ b/src/main/java/com/github/nkzawa/engineio/client/Transport.java
@@ -121,6 +121,11 @@ public abstract class Transport extends Emitter {
 
     public static class Options {
 
+        /**
+         * Cookie value for handshake.
+         */
+        public String cookie;
+
         public String hostname;
         public String path;
         public String timestampParam;
diff --git a/src/main/java/com/github/nkzawa/engineio/client/transports/PollingXHR.java b/src/main/java/com/github/nkzawa/engineio/client/transports/PollingXHR.java
index d59adb4..779e8fc 100644
--- a/src/main/java/com/github/nkzawa/engineio/client/transports/PollingXHR.java
+++ b/src/main/java/com/github/nkzawa/engineio/client/transports/PollingXHR.java
@@ -17,9 +17,11 @@ public class PollingXHR extends Polling {
 
     private Request sendXhr;
     private Request pollXhr;
+    private String cookie;
 
     public PollingXHR(Options opts) {
         super(opts);
+        this.cookie = opts.cookie;
     }
 
     protected Request request() {
@@ -31,6 +33,7 @@ public class PollingXHR extends Polling {
             opts = new Request.Options();
         }
         opts.uri = this.uri();
+        opts.cookie = this.cookie;
         return new Request(opts);
     }
 
@@ -110,12 +113,14 @@ public class PollingXHR extends Polling {
         String method;
         String uri;
         String data;
+        String cookie;
         HttpURLConnection xhr;
 
         public Request(Options opts) {
             this.method = opts.method != null ? opts.method : "GET";
             this.uri = opts.uri;
             this.data = opts.data;
+            this.cookie = opts.cookie;
         }
 
         public void create() {
@@ -134,6 +139,10 @@ public class PollingXHR extends Polling {
                 xhr.setRequestProperty("Content-type", "text/plain;charset=UTF-8");
             }
 
+            if (this.cookie != null) {
+                xhr.setRequestProperty("Cookie", this.cookie);
+            }
+
             logger.fine(String.format("sending xhr with url %s | data %s", this.uri, this.data));
             xhrService.submit(new Runnable() {
                 @Override
@@ -201,6 +210,7 @@ public class PollingXHR extends Polling {
             public String uri;
             public String method;
             public String data;
+            public String cookie;
         }
     }
 }
diff --git a/src/test/java/com/github/nkzawa/engineio/client/ServerConnectionTest.java b/src/test/java/com/github/nkzawa/engineio/client/ServerConnectionTest.java
index 4d85815..0bd1654 100644
--- a/src/test/java/com/github/nkzawa/engineio/client/ServerConnectionTest.java
+++ b/src/test/java/com/github/nkzawa/engineio/client/ServerConnectionTest.java
@@ -217,4 +217,31 @@ public class ServerConnectionTest {
 
         socket.close();
     }
+
+    @Test(timeout = TIMEOUT)
+    public void cookie() throws URISyntaxException, InterruptedException {
+        final BlockingQueue<String> messages = new LinkedBlockingQueue<String>();
+
+        Socket.Options opts = new Socket.Options();
+        opts.cookie = "foo=1;";
+
+        socket = new Socket("ws://localhost:" + PORT, opts) {
+            @Override
+            public void onopen() {}
+
+            @Override
+            public void onmessage(String data) {
+                System.out.println("onmessage: " + data);
+                messages.offer(data);
+            }
+
+            @Override
+            public void onclose() {}
+        };
+        socket.open();
+
+        assertThat(messages.take(), is("hello client"));
+        assertThat(messages.take(), is(opts.cookie));
+        socket.close();
+    }
 }
diff --git a/src/test/resources/index.js b/src/test/resources/index.js
index 18d4ed4..86732b9 100644
--- a/src/test/resources/index.js
+++ b/src/test/resources/index.js
@@ -7,6 +7,11 @@ var engine = require('engine.io')
 server.on('connection', function(socket) {
   socket.send('hello client');
 
+  if (socket.request.headers.cookie) {
+      console.log('cookie:', socket.request.headers.cookie);
+      socket.send(socket.request.headers.cookie);
+  }
+
   socket.on('packet', function(packet) {
     console.log('packet:', packet);
   });