diff --git a/PYTHON-MANIFEST.in b/PYTHON-MANIFEST.in
index f3ef08c8263..aa044d84074 100644
--- a/PYTHON-MANIFEST.in
+++ b/PYTHON-MANIFEST.in
@@ -1,4 +1,4 @@
-recursive-include src/python/grpcio/grpc *.c *.h *.py *.pyx *.pxd *.pxi *.python *.pem
+recursive-include src/python/grpcio/grpc *.c *.h *.inc *.py *.pyx *.pxd *.pxi *.python *.pem
 recursive-exclude src/python/grpcio/grpc/_cython *.so *.pyd
 graft src/python/grpcio/grpcio.egg-info
 graft src/core