diff --git a/gnu/packages/base.scm b/gnu/packages/base.scm
index ca440c242c..a603688a6b 100644
--- a/gnu/packages/base.scm
+++ b/gnu/packages/base.scm
@@ -2,7 +2,7 @@
 ;;; Copyright © 2012, 2013, 2014, 2015 Ludovic Courtès <ludo@gnu.org>
 ;;; Copyright © 2014 Andreas Enge <andreas@enge.fr>
 ;;; Copyright © 2012 Nikita Karetnikov <nikita@karetnikov.org>
-;;; Copyright © 2014 Mark H Weaver <mhw@netris.org>
+;;; Copyright © 2014, 2015 Mark H Weaver <mhw@netris.org>
 ;;; Copyright © 2014 Alex Kost <alezost@gmail.com>
 ;;;
 ;;; This file is part of GNU Guix.
@@ -385,6 +385,7 @@ included.")
 
    (arguments
     `(#:out-of-source? #t
+      #:parallel-build? #f ; There's at least one race in the build.
       #:configure-flags
       (list "--enable-add-ons"
             "--sysconfdir=/etc"