diff --git a/setup.py b/setup.py
index 720d6de..9e554bb 100644
--- a/setup.py
+++ b/setup.py
@@ -6,14 +6,5 @@
 from setuptools import setup
 
 setup(
-    ext_modules=[
-        Extension(
-            'gradunwarp.core.{}_ext'.format(mod),
-            include_dirs=[get_include()],
-            sources=['gradunwarp/core/{}_ext.c'.format(mod)],
-            extra_compile_args=['-O3'],
-        )
-        for mod in ('interp3', 'legendre', 'transform_coordinates')
-    ],
     scripts=['gradunwarp/core/gradient_unwarp.py'],
 )