diff --git a/pyres/__init__.py b/pyres/__init__.py
index 011cd88..fa0ea0f 100644
--- a/pyres/__init__.py
+++ b/pyres/__init__.py
@@ -300,7 +300,7 @@ def enqueue_at_from_string(self, datetime, klass_as_string, queue, *args, **kwar
     def delayed_push(self, datetime, item):
         key = int(time.mktime(datetime.timetuple()))
         self.redis.rpush('resque:delayed:%s' % key, ResQ.encode(item))
-        self.redis.zadd('resque:delayed_queue_schedule', key, key)
+        self.redis.zadd('resque:delayed_queue_schedule', {key: key})
 
     def delayed_queue_peek(self, start, count):
         return [int(item) for item in self.redis.zrange(