diff --git a/tarantool/response.py b/tarantool/response.py
index 7b8a5636..9516cd39 100644
--- a/tarantool/response.py
+++ b/tarantool/response.py
@@ -238,7 +238,7 @@ def __str__(self):
                 }
             }, sort_keys = True, indent = 4)
         output = []
-        for tpl in self._data:
+        for tpl in self._data or ():
             output.extend(("- ", repr(tpl), "\n"))
         if len(output) > 0:
             output.pop()