diff --git a/lib/http.js b/lib/http.js
index 12012d0587..3537b70b79 100644
--- a/lib/http.js
+++ b/lib/http.js
@@ -862,9 +862,11 @@ ServerResponse.prototype.writeHeader = function() {
 };
 
 
-function ClientRequest(options) {
+function ClientRequest(options, defaultPort) {
   OutgoingMessage.call(this);
 
+  if (!defaultPort) defaultPort = 80;
+
   var method = this.method = (options.method || 'GET').toUpperCase();
   this.path = options.path || '/';
 
@@ -879,7 +881,11 @@ function ClientRequest(options) {
     }
     // Host header set by default.
     if (options.host && !this.getHeader('host')) {
-      this.setHeader("Host", options.host);
+      var hostHeader = options.host;
+      if (options.port && +options.port !== defaultPort) {
+        hostHeader += ':' + options.port;
+      }
+      this.setHeader("Host", hostHeader);
     }
   }
 
@@ -1110,7 +1116,7 @@ exports._connectionListener = connectionListener;
 function Agent(options) {
   this.options = options;
   this.host = options.host;
-  this.port = options.port || 80;
+  this.port = options.port || this.defaultPort;
 
   this.queue = [];
   this.sockets = [];
@@ -1122,11 +1128,11 @@ exports.Agent = Agent;
 
 Agent.defaultMaxSockets = 5;
 
-
+Agent.prototype.defaultPort = 80;
 Agent.prototype.appendMessage = function(options) {
   var self = this;
 
-  var req = new ClientRequest(options);
+  var req = new ClientRequest(options, this.defaultPort);
   this.queue.push(req);
   req._queue = this.queue;
 
diff --git a/lib/https.js b/lib/https.js
index 595f8a962b..bd2e4617a4 100644
--- a/lib/https.js
+++ b/lib/https.js
@@ -54,6 +54,9 @@ function Agent(options) {
 inherits(Agent, http.Agent);
 
 
+Agent.prototype.defaultPort = 443;
+
+
 Agent.prototype._getConnection = function(host, port, cb) {
   var s = tls.connect(port, host, this.options, function() {
     // do other checks here?
diff --git a/test/simple/test-http-host-headers.js b/test/simple/test-http-host-headers.js
new file mode 100644
index 0000000000..7db175a4d0
--- /dev/null
+++ b/test/simple/test-http-host-headers.js
@@ -0,0 +1,150 @@
+// Copyright Joyent, Inc. and other Node contributors.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the
+// "Software"), to deal in the Software without restriction, including
+// without limitation the rights to use, copy, modify, merge, publish,
+// distribute, sublicense, and/or sell copies of the Software, and to permit
+// persons to whom the Software is furnished to do so, subject to the
+// following conditions:
+//
+// The above copyright notice and this permission notice shall be included
+// in all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
+// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
+// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+// USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+var http = require('http'),
+    https = require('https'),
+    fs = require('fs'),
+    common = require('../common'),
+    assert = require('assert'),
+    options = {
+      key: fs.readFileSync(common.fixturesDir + '/keys/agent1-key.pem'),
+      cert: fs.readFileSync(common.fixturesDir + '/keys/agent1-cert.pem')
+    },
+    httpServer = http.createServer(reqHandler),
+    httpsServer = https.createServer(options, reqHandler);
+
+function reqHandler(req, res) {
+  console.log('Got request: ' + req.headers.host + ' ' + req.url);
+  assert.equal(req.headers.host, 'localhost:' + common.PORT,
+               'Wrong host header for req[' + req.url + ']: ' +
+               req.headers.host);
+  res.writeHead(200, {});
+  //process.nextTick(function() { res.end('ok'); });
+  res.end('ok');
+}
+
+function thrower(er) {
+  throw er;
+}
+
+testHttp();
+
+function testHttp() {
+
+  console.log('testing http on port ' + common.PORT);
+
+  var counter = 0;
+
+  function cb() {
+    counter--;
+    console.log('back from http request. counter = ' + counter);
+    if (counter === 0) {
+      httpServer.close();
+      testHttps();
+    }
+  }
+
+  httpServer.listen(common.PORT, function(er) {
+    console.error('listening on ' + common.PORT);
+
+    if (er) throw er;
+
+    http.get({ method: 'GET',
+      path: '/' + (counter++),
+      host: 'localhost',
+      //agent: false,
+      port: common.PORT }, cb).on('error', thrower);
+
+    http.request({ method: 'GET',
+      path: '/' + (counter++),
+      host: 'localhost',
+      //agent: false,
+      port: common.PORT }, cb).on('error', thrower).end();
+
+    http.request({ method: 'POST',
+      path: '/' + (counter++),
+      host: 'localhost',
+      //agent: false,
+      port: common.PORT }, cb).on('error', thrower).end();
+
+    http.request({ method: 'PUT',
+      path: '/' + (counter++),
+      host: 'localhost',
+      //agent: false,
+      port: common.PORT }, cb).on('error', thrower).end();
+
+    http.request({ method: 'DELETE',
+      path: '/' + (counter++),
+      host: 'localhost',
+      //agent: false,
+      port: common.PORT }, cb).on('error', thrower).end();
+  });
+}
+
+function testHttps() {
+
+  console.log('testing https on port ' + common.PORT);
+
+  var counter = 0;
+
+  function cb() {
+    counter--;
+    console.log('back from https request. counter = ' + counter);
+    if (counter === 0) {
+      httpsServer.close();
+      console.log('ok');
+    }
+  }
+
+  httpsServer.listen(common.PORT, function(er) {
+    if (er) throw er;
+
+    https.get({ method: 'GET',
+      path: '/' + (counter++),
+      host: 'localhost',
+      //agent: false,
+      port: common.PORT }, cb).on('error', thrower);
+
+    https.request({ method: 'GET',
+      path: '/' + (counter++),
+      host: 'localhost',
+      //agent: false,
+      port: common.PORT }, cb).on('error', thrower).end();
+
+    https.request({ method: 'POST',
+      path: '/' + (counter++),
+      host: 'localhost',
+      //agent: false,
+      port: common.PORT }, cb).on('error', thrower).end();
+
+    https.request({ method: 'PUT',
+      path: '/' + (counter++),
+      host: 'localhost',
+      //agent: false,
+      port: common.PORT }, cb).on('error', thrower).end();
+
+    https.request({ method: 'DELETE',
+      path: '/' + (counter++),
+      host: 'localhost',
+      //agent: false,
+      port: common.PORT }, cb).on('error', thrower).end();
+  });
+}