diff --git a/src/ng/http.js b/src/ng/http.js
index 0ae6d0ef1b81..3088e422f32d 100644
--- a/src/ng/http.js
+++ b/src/ng/http.js
@@ -119,7 +119,7 @@ function $HttpProvider() {
       if (isString(data)) {
         // strip json vulnerability protection prefix
         data = data.replace(PROTECTION_PREFIX, '');
-        var contentType = headers('Content-Type');
+        var contentType = headers ? headers('Content-Type') : null;
         if ((contentType && contentType.indexOf(APPLICATION_JSON) === 0) ||
             (JSON_START.test(data) && JSON_END.test(data))) {
           data = fromJson(data);