diff --git a/setup.py b/setup.py
index 9e3db24..df0a96e 100644
--- a/setup.py
+++ b/setup.py
@@ -2,7 +2,7 @@
 
 setup(
     ext_modules=[
-        Extension("gdmath.vector", ["src/gdmath/vector.c"])
+        Extension("gdmath.vector", ["src/gdmath/vector.pyx"])
     ],
     packages=find_packages(
         where="src",