diff --git a/pkgs/development/python-modules/base36/default.nix b/pkgs/development/python-modules/base36/default.nix
index e1fd894a2922..ff9d22aa24ea 100644
--- a/pkgs/development/python-modules/base36/default.nix
+++ b/pkgs/development/python-modules/base36/default.nix
@@ -2,13 +2,14 @@
   lib,
   buildPythonPackage,
   fetchFromGitHub,
+  setuptools,
   pytestCheckHook,
 }:
 
 buildPythonPackage rec {
   pname = "base36";
   version = "0.1.1";
-  format = "setuptools";
+  pyproject = true;
 
   src = fetchFromGitHub {
     owner = "tonyseek";
@@ -17,6 +18,8 @@ buildPythonPackage rec {
     sha256 = "076nmk9s0zkmgs2zqzkaqij5cmzhf4mrhivbb9n6cvz52i1mppr5";
   };
 
+  build-system = [ setuptools ];
+
   postPatch = ''
     substituteInPlace setup.cfg \
       --replace "[pytest]" "[tool:pytest]" \