diff --git a/setup.py b/setup.py
index c3ed123ff..962e77b90 100644
--- a/setup.py
+++ b/setup.py
@@ -19,7 +19,8 @@
 
 # msgpack pure python data corruption was fixed in 0.4.6.
 # Also, we might use some rather recent API features.
-install_requires=['msgpack-python>=0.4.6', ]
+# Note: 0.4.7 is also OK, but has no Python 3.2 support any more.
+install_requires=['msgpack-python==0.4.6', ]
 
 
 from setuptools import setup, Extension