diff --git a/pkgs/development/python-modules/titlecase/default.nix b/pkgs/development/python-modules/titlecase/default.nix
index c1de2454e4b..acc8b9c5670 100644
--- a/pkgs/development/python-modules/titlecase/default.nix
+++ b/pkgs/development/python-modules/titlecase/default.nix
@@ -1,4 +1,4 @@
-{buildPythonPackage, lib, nose, fetchPypi}:
+{ buildPythonPackage, lib, nose, fetchPypi, regex }:
 
 buildPythonPackage rec {
   pname = "titlecase";
@@ -9,6 +9,8 @@ buildPythonPackage rec {
     sha256 = "16e279edf085293bc9c44a68ce959c7d6cd5c653e6b5669a3a3640015cb63eb6";
   };
 
+  propagatedBuildInputs = [ regex ];
+
   checkInputs = [ nose ];
 
   meta = {
@@ -17,4 +19,3 @@ buildPythonPackage rec {
     license = lib.licenses.mit;
   };
 }
-