diff --git a/lib/hyperagent/miniscore.js b/lib/hyperagent/miniscore.js
index 196b38d..947f6dd 100644
--- a/lib/hyperagent/miniscore.js
+++ b/lib/hyperagent/miniscore.js
@@ -73,7 +73,7 @@ _.defaults = function (obj) {
   _.each(Array.prototype.slice.call(arguments, 1), function (source) {
     if (source) {
       for (var prop in source) {
-        if (obj[prop] === null || obj[prop] === undefined) {
+        if (obj[prop] === undefined) {
           obj[prop] = source[prop];
         }
       }