diff --git a/build-aux/check-available-binaries.scm b/build-aux/check-available-binaries.scm
index 92810795e1..d5163a9503 100644
--- a/build-aux/check-available-binaries.scm
+++ b/build-aux/check-available-binaries.scm
@@ -1,5 +1,5 @@
 ;;; GNU Guix --- Functional package management for GNU
-;;; Copyright © 2013 Ludovic Courtès <ludo@gnu.org>
+;;; Copyright © 2013, 2014 Ludovic Courtès <ludo@gnu.org>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -48,6 +48,7 @@
                     drv)
             #f))))
 
+  (set-build-options store #:use-substitutes? #t)
   (let ((result (every (compose (warn (cut has-substitutes? store <>))
                                 derivation->output-path)
                        total)))