diff --git a/guix/scripts/size.scm b/guix/scripts/size.scm
index be1e8ca087..8a7974729b 100644
--- a/guix/scripts/size.scm
+++ b/guix/scripts/size.scm
@@ -123,13 +123,20 @@ (define (requisites* item)
                        store)))
       (values (requisites store item) store))))
 
-(define (store-profile item)
+(define (mappend-map mproc lst)
+  "Apply MPROC to each item of LST and concatenate the resulting list."
+  (with-monad %store-monad
+    (>>= (mapm %store-monad mproc lst)
+         (lambda (lstlst)
+           (return (concatenate lstlst))))))
+
+(define (store-profile items)
   "Return as a monadic value a list of <profile> objects representing the
-profile of ITEM and its requisites."
-  (mlet* %store-monad ((refs  (>>= (requisites* item)
+profile of ITEMS and their requisites."
+  (mlet* %store-monad ((refs  (>>= (mappend-map requisites* items)
                                    (lambda (refs)
                                      (return (delete-duplicates
-                                              (cons item refs))))))
+                                              (append items refs))))))
                        (sizes (mapm %store-monad
                                     (lambda (item)
                                       (>>= (file-size item)
@@ -286,7 +293,7 @@ (define (guix-size . args)
 
               (run-with-store store
                 (mlet* %store-monad ((item    (ensure-store-item file))
-                                     (profile (store-profile item)))
+                                     (profile (store-profile (list item))))
                   (if map-file
                       (begin
                         (profile->page-map profile map-file)
diff --git a/tests/size.scm b/tests/size.scm
index fcd590283d..068ebc1d68 100644
--- a/tests/size.scm
+++ b/tests/size.scm
@@ -1,5 +1,5 @@
 ;;; GNU Guix --- Functional package management for GNU
-;;; Copyright © 2015 Ludovic Courtès <ludo@gnu.org>
+;;; Copyright © 2015, 2016 Ludovic Courtès <ludo@gnu.org>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -54,7 +54,7 @@ (define (matching-profile item)
     (mbegin %store-monad
       (built-derivations (list file2))
       (mlet %store-monad ((profiles (store-profile
-                                     (derivation->output-path file2)))
+                                     (list (derivation->output-path file2))))
                           (bash     (interned-file
                                      (search-bootstrap-binary
                                       "bash" (%current-system)) "bash"