diff --git a/tarantool/request.py b/tarantool/request.py
index 8564ec18..c4f8fc22 100644
--- a/tarantool/request.py
+++ b/tarantool/request.py
@@ -4,6 +4,7 @@
 Request types definitions
 '''
 
+import sys
 import collections
 import msgpack
 import hashlib
@@ -101,7 +102,7 @@ def __init__(self, conn):
         # connection encoding is not None. If encoding is None,
         # pack bytes as mp_str and unpack mp_str to bytes. mp_bin is
         # unsupported in this mode.
-        if conn.encoding is None:
+        if conn.encoding is None or sys.version_info.major == 2:
             packer_kwargs['use_bin_type'] = False
         else:
             packer_kwargs['use_bin_type'] = True