diff --git a/README.md b/README.md
index 6b97fe5..2a8baa5 100644
--- a/README.md
+++ b/README.md
@@ -57,6 +57,7 @@ Google it.
     -A, --amount <connections>      the amount of persistent connections to generate
     -C, --concurrent <connections>  how many concurrent-connections per second
     -M, --messages <messages>       messages to be send per connection
+    -H, --header [header]           a header to pass to each connection
     -P, --protocol <protocol>       WebSocket protocol version
     -B, --buffer <size>             size of the messages that are send
     -W, --workers <cpus>            workers to be spawned
diff --git a/bin/thor b/bin/thor
index 9db08f2..31e4e7e 100755
--- a/bin/thor
+++ b/bin/thor
@@ -7,18 +7,33 @@ var Metrics = require('../metrics')
   , path = require('path')
   , os = require('os');
 
+function collect(val, memo) {
+  if(!memo){
+    memo = [];
+  }
+  memo.push(val);
+  return memo;
+}
+
+function parseInteger(val){
+  if(val){
+    return parseInt(val);
+  }
+}
+
 //
 // Setup the Command-Line Interface.
 //
 var cli = require('commander');
 
 cli.usage('[options] ws://localhost')
-   .option('-A, --amount <connections>', 'the amount of persistent connections to generate', parseInt, 10000)
-   .option('-C, --concurrent <connections>', 'how many concurrent-connections per second', parseInt, 0)
-   .option('-M, --messages <messages>', 'messages to be send per connection', parseInt, 1)
-   .option('-P, --protocol <protocol>', 'WebSocket protocol version', parseInt, 13)
-   .option('-B, --buffer <size>', 'size of the messages that are send', parseInt, 1024)
-   .option('-W, --workers <cpus>', 'workers to be spawned', parseInt, os.cpus().length)
+   .option('-A, --amount <connections>', 'the amount of persistent connections to generate', parseInteger, 10000)
+   .option('-C, --concurrent <connections>', 'how many concurrent-connections per second', parseInteger, 0)
+   .option('-M, --messages <messages>', 'messages to be send per connection', parseInteger, 1)
+   .option('-H, --header [header]', 'a header to pass to each connection', collect, [])
+   .option('-P, --protocol <protocol>', 'WebSocket protocol version', parseInteger, 13)
+   .option('-B, --buffer <size>', 'size of the messages that are send', parseInteger, 1024)
+   .option('-W, --workers <cpus>', 'workers to be spawned', parseInteger, os.cpus().length)
    .option('-G, --generator <file>', 'custom message generators')
    .option('-M, --masked', 'send the messaged with a mask')
    .option('-b, --binary', 'send binary messages instead of utf-8')
@@ -47,6 +62,21 @@ var cluster = require('cluster')
   , received = 0
   , robin = [];
 
+//
+// Process headers
+//
+var headers = {};
+cli.header.forEach(function(header){
+  var keyValue = header.split(':');
+  var key = keyValue[0];
+  var value = keyValue[1];
+  if(!key || !value){
+    console.warn('Header \'' +  + '\' is wrongly defined. A header should looks like \'key:value\'.');
+    return;
+  }
+  headers[key.trim()] = value.trim();
+});
+
 cluster.setupMaster({
     exec: path.resolve(__dirname, '../mjolnir.js')
   , silent: false
@@ -56,7 +86,8 @@ cluster.setupMaster({
       : path.resolve(__dirname, '../generator.js'),
       cli.protocol,
       !!cli.masked,
-      !!cli.binary
+      !!cli.binary,
+      JSON.stringify(headers)
     ]
 });
 
diff --git a/mjolnir.js b/mjolnir.js
index c22f517..1434948 100644
--- a/mjolnir.js
+++ b/mjolnir.js
@@ -14,7 +14,8 @@ var session = require(process.argv[2]);
 //
 var masked = process.argv[4] === 'true'
   , binary = process.argv[5] === 'true'
-  , protocol = +process.argv[3] || 13;
+  , protocol = +process.argv[3] || 13
+  , headers = JSON.parse(process.argv[6]);
 
 process.on('message', function message(task) {
   var now = Date.now();
@@ -40,8 +41,9 @@ process.on('message', function message(task) {
   // End of the line, we are gonna start generating new connections.
   if (!task.url) return;
 
-  var socket = new Socket(task.url, {
-    protocolVersion: protocol
+  var socket = new Socket(task.url, [], {
+    protocolVersion: protocol,
+    headers: headers
   });
 
   socket.on('open', function open() {
diff --git a/package.json b/package.json
index 48c2b49..205468b 100644
--- a/package.json
+++ b/package.json
@@ -18,7 +18,7 @@
   "author": "Arnout Kazemier <opensource@observe.it>",
   "license": "MIT",
   "dependencies": {
-    "commander": "1.1.x",
+    "commander": "2.9.0",
     "async": "0.2.x",
     "tab": "0.1.x",
     "colors": "0.6.x",