diff --git a/pkgs/development/python-modules/blosc2/default.nix b/pkgs/development/python-modules/blosc2/default.nix
index 027dd0ca8e19f3d..87f23b04dcf0027 100644
--- a/pkgs/development/python-modules/blosc2/default.nix
+++ b/pkgs/development/python-modules/blosc2/default.nix
@@ -35,6 +35,11 @@ buildPythonPackage rec {
     hash = "sha256-nbPMLkTye0/Q05ubE35LssN677sUIQErPTxjAtSuGgI=";
   };
 
+  postPatch = ''
+    substituteInPlace requirements-runtime.txt \
+      --replace "pytest" ""
+  '';
+
   nativeBuildInputs = [
     cmake
     cython