diff --git a/python-lxml.spec b/python-lxml.spec
index 934f3a7..84c5aab 100644
--- a/python-lxml.spec
+++ b/python-lxml.spec
@@ -53,6 +53,9 @@ Python 3 version.
 %prep
 %autosetup -n %{modname}-%{version}
 
+# Remove pregenerated Cython C sources
+find -name '*.c' | xargs rm
+
 %build
 export WITH_CYTHON=true
 %py2_build