diff --git a/firefox.sh.in b/firefox.sh.in
index 06aadbe..81d3cbb 100644
--- a/firefox.sh.in
+++ b/firefox.sh.in
@@ -144,11 +144,11 @@ GNOME_DISABLE_CRASH_DIALOG=1
 export GNOME_DISABLE_CRASH_DIALOG
 
 ##
-## Use $MOZ_TMPDIR if set. Otherwise use /var/tmp instead of /tmp
+## Use $TMPDIR if set. Otherwise use /var/tmp instead of /tmp
 ## because of 1GB /tmp limit in Fedora 18 and later.
 ## See: https://bugzilla.redhat.com/show_bug.cgi?id=867073
 ##
-TMPDIR="${MOZ_TMPDIR:-/var/tmp}"
+TMPDIR="${TMPDIR:-/var/tmp}"
 export TMPDIR
 
 # OK, here's where all the real work gets done
diff --git a/firefox.spec b/firefox.spec
index 2b76c6c..871b580 100644
--- a/firefox.spec
+++ b/firefox.spec
@@ -55,7 +55,7 @@
 Summary:        Mozilla Firefox Web browser
 Name:           firefox
 Version:        21.0
-Release:        3%{?pre_tag}%{?dist}
+Release:        4%{?pre_tag}%{?dist}
 URL:            http://www.mozilla.org/projects/firefox/
 License:        MPLv1.1 or GPLv2+ or LGPLv2+
 Group:          Applications/Internet
@@ -442,6 +442,9 @@ gtk-update-icon-cache %{_datadir}/icons/hicolor &>/dev/null || :
 #---------------------------------------------------------------------
 
 %changelog
+* Thu May 23 2013 Jan Horak <jhorak@redhat.com> - 21.0-4
+- Do not override user defined TMPDIR variable
+
 * Thu May 16 2013 Martin Stransky <stransky@redhat.com> - 21.0-3
 - Fixed extension compatibility dialog (rhbz#963422)