diff --git a/pkgs/development/python-modules/pycares/default.nix b/pkgs/development/python-modules/pycares/default.nix
index 305c2e01c566..868dbeca6c6c 100644
--- a/pkgs/development/python-modules/pycares/default.nix
+++ b/pkgs/development/python-modules/pycares/default.nix
@@ -24,6 +24,10 @@ buildPythonPackage rec {
     idna
   ];
 
+  propagatedNativeBuildInputs = [
+    cffi
+  ];
+
   # Requires network access
   doCheck = false;