diff --git a/pkgs/applications/networking/browsers/firefox/default.nix b/pkgs/applications/networking/browsers/firefox/default.nix
index 60befdbaad5..2892aa328b0 100644
--- a/pkgs/applications/networking/browsers/firefox/default.nix
+++ b/pkgs/applications/networking/browsers/firefox/default.nix
@@ -15,14 +15,14 @@
 
 assert stdenv.gcc ? libc && stdenv.gcc.libc != null;
 
-let version = "33.1.1"; in
+let version = "34.0.5"; in
 
 stdenv.mkDerivation rec {
   name = "firefox-${version}";
 
   src = fetchurl {
     url = "http://ftp.mozilla.org/pub/mozilla.org/firefox/releases/${version}/source/firefox-${version}.source.tar.bz2";
-    sha1 = "1e9e3176e7d221c4f2ce479f37ee7c432236a0ec";
+    sha1 = "33654d38268d1d1f71105f48bbe97cf720f47be2";
   };
 
   buildInputs =