diff --git a/MANIFEST.in b/MANIFEST.in
index ecc747a..b5f518e 100644
--- a/MANIFEST.in
+++ b/MANIFEST.in
@@ -6,4 +6,5 @@ include sample.settings.py
 recursive-include contrib/ *.py
 recursive-include overviewer_core/ *.py
 recursive-include overviewer_core/src/ *.c *.h
+recursive-include overviewer_core/src/primitives/ *.c *.h
 recursive-include overviewer_core/data/ *