diff --git a/pkgs/development/python-modules/cytoolz/default.nix b/pkgs/development/python-modules/cytoolz/default.nix
index befb71963c79..574e717759e7 100644
--- a/pkgs/development/python-modules/cytoolz/default.nix
+++ b/pkgs/development/python-modules/cytoolz/default.nix
@@ -13,14 +13,14 @@
 
 buildPythonPackage rec {
   pname = "cytoolz";
-  version = "0.12.3";
+  version = "1.0.0";
   pyproject = true;
 
   disabled = isPy27 || isPyPy;
 
   src = fetchPypi {
     inherit pname version;
-    hash = "sha256-RQPcWfTO1TpUZDJyxh3DBdHbv719a98paUjenzTDooI=";
+    hash = "sha256-60U7MBghUvmRelGJt9mQRrbOkM34rrD+/0smg+YA3v0=";
   };
 
   nativeBuildInputs = [