diff --git a/lib/http-proxy/common.js b/lib/http-proxy/common.js
index 6aee0bd..24ed323 100644
--- a/lib/http-proxy/common.js
+++ b/lib/http-proxy/common.js
@@ -150,7 +150,7 @@ common.urlJoin = function() {
   retSegs = [
     args.filter(function filter(a) {
       return !!a;
-    }).join('/').replace(/\/+/g, '/')
+    }).join('/').replace(/\/+/g, '/').replace(/:\//g, '://')
   ];
 
   // Only join the query string if it exists so we don't have trailing a '?'