diff --git a/MANIFEST b/MANIFEST
index 6983a33..1fe22ec 100644
--- a/MANIFEST
+++ b/MANIFEST
@@ -2,6 +2,7 @@ setup.py
 msgpack/pack.h
 msgpack/unpack.h
 msgpack/_msgpack.pyx
+msgpack/__init__.py
 include/msgpack/pack_define.h
 include/msgpack/pack_template.h
 include/msgpack/unpack_define.h