diff --git a/MANIFEST.in b/MANIFEST.in
index 4bd67e01244de7f932f2dceaa7ba1a1389ae517f..11f8ea532781e7b79d90977e38931fb635e764e3 100644
--- a/MANIFEST.in
+++ b/MANIFEST.in
@@ -5,6 +5,7 @@ include isl/imath/*.h
 include isl/imath_wrap/*.h
 include isl/imath_wrap/*.c
 include isl/include/isl/*.h
+include isl/include/isl/*.c
 include isl/include/isl/deprecated/*.h
 include isl-supplementary/isl/*.h
 include isl-supplementary/*.h