diff --git a/lib/XMLHttpRequest.js b/lib/XMLHttpRequest.js
index ad4f5f3..fb2f7d4 100644
--- a/lib/XMLHttpRequest.js
+++ b/lib/XMLHttpRequest.js
@@ -330,8 +330,11 @@ exports.XMLHttpRequest = function() {
     }
 
     // Set Basic Auth if necessary
-    if (settings.user) {
-      if (typeof settings.password == "undefined") {
+    if (settings.user || settings.password) {
+      if (settings.user == null) {
+        settings.user = "";
+      }
+      if (settings.password == null) {
         settings.password = "";
       }
       var authBuf = new Buffer(settings.user + ":" + settings.password);