diff --git a/setup.py b/setup.py
index d5b843fdacecc4341a5cddf36459347b259be83f..4d71848bff02933bc4a82f4a8230fd8e88efb1f8 100644
--- a/setup.py
+++ b/setup.py
@@ -206,14 +206,13 @@ PACKAGE_DIRECTORIES = {
 
 INSTALL_REQUIRES = (
     'six>=1.5.2',
-    'enum34>=1.0.4',
     # TODO(atash): eventually split the grpcio package into a metapackage
     # depending on protobuf and the runtime component (independent of protobuf)
     'protobuf>=3.2.0',
 )
 
 if not PY3:
-  INSTALL_REQUIRES += ('futures>=2.2.0',)
+  INSTALL_REQUIRES += ('futures>=2.2.0', 'enum34>=1.0.4')
 
 SETUP_REQUIRES = INSTALL_REQUIRES + (
     'sphinx>=1.3',