diff --git a/pykafka/simpleconsumer.py b/pykafka/simpleconsumer.py
index f2cf5e2fc..4407c82f5 100644
--- a/pykafka/simpleconsumer.py
+++ b/pykafka/simpleconsumer.py
@@ -506,7 +506,7 @@ def consume(self, block=True, unblock_event=None):
             if not self._slot_available.is_set():
                 self._slot_available.set()
 
-        if self._deserializer is not None:
+        if self._deserializer is not None and ret is not None:
             ret.value, ret.partition_key = self._deserializer(ret.value,
                                                               ret.partition_key)
         return ret