diff --git a/pkgs/development/python-modules/duckdb/default.nix b/pkgs/development/python-modules/duckdb/default.nix
index d7878bd6a44d..c61dfc9f4da4 100644
--- a/pkgs/development/python-modules/duckdb/default.nix
+++ b/pkgs/development/python-modules/duckdb/default.nix
@@ -19,6 +19,7 @@ buildPythonPackage rec {
 
   preConfigure = ''
     cd tools/pythonpkg
+    substituteInPlace setup.py --replace "multiprocessing.cpu_count()" "$NIX_BUILD_CORES"
   '';
 
   SETUPTOOLS_SCM_PRETEND_VERSION = version;