diff --git a/flask/helpers.py b/flask/helpers.py
index e633e1b9..72a961a8 100644
--- a/flask/helpers.py
+++ b/flask/helpers.py
@@ -133,13 +133,17 @@ def jsonify(*args, **kwargs):
     """
     if __debug__:
         _assert_have_json()
+
+    padded = kwargs.get('padded', False)
     if 'padded' in kwargs:
-        if isinstance(kwargs['padded'], str):
-            callback = request.args.get(kwargs['padded']) or 'jsonp'
+        del kwargs['padded']
+
+    if padded:
+        if isinstance(padded, str):
+            callback = request.args.get(padded) or 'jsonp'
         else:
             callback = request.args.get('callback') or \
                        request.args.get('jsonp') or 'jsonp'
-        del kwargs['padded']
         json_str = json.dumps(dict(*args, **kwargs), indent=None)
         content = str(callback) + "(" + json_str + ")"
         return current_app.response_class(content, mimetype='application/javascript')