diff --git a/lib/http-proxy/common.js b/lib/http-proxy/common.js
index 24ed323c7..f7724b676 100644
--- a/lib/http-proxy/common.js
+++ b/lib/http-proxy/common.js
@@ -74,7 +74,7 @@ common.setupOutgoing = function(outgoing, options, req, forward) {
   outgoing.path = common.urlJoin(targetPath, outgoingPath);
 
   if (options.changeOrigin) {
-    outgoing.headers.host = outgoing.host;
+    outgoing.headers.host = outgoing.host + ':' + outgoing.port;
   }
 
   return outgoing;