diff --git a/lisp/arc-mode.el b/lisp/arc-mode.el
index a20770c9f53..d365e59c26d 100644
--- a/lisp/arc-mode.el
+++ b/lisp/arc-mode.el
@@ -122,7 +122,7 @@
 (defcustom archive-tmpdir
   (make-temp-name
    (expand-file-name (if (eq system-type 'ms-dos) "ar" "archive.tmp")
-		     (or (getenv "TMPDIR") (getenv "TMP") "/tmp")))
+		     system-tmp-directory))
   "*Directory for temporary files made by arc-mode.el"
   :type 'directory
   :group 'archive)