diff --git a/pkgs/servers/sql/postgresql/8.4.x.nix b/pkgs/servers/sql/postgresql/8.4.x.nix
index bbf30c02636e..0d40e4708d2a 100644
--- a/pkgs/servers/sql/postgresql/8.4.x.nix
+++ b/pkgs/servers/sql/postgresql/8.4.x.nix
@@ -12,7 +12,7 @@ stdenv.mkDerivation rec {
 
   buildInputs = [zlib ncurses readline];
 
-  LC_ALL = "en_US";
+  LC_ALL = "C";
 
   passthru = { inherit readline; };