diff --git a/gnu/services/xorg.scm b/gnu/services/xorg.scm
index 06d72b5f60..e87cb4d845 100644
--- a/gnu/services/xorg.scm
+++ b/gnu/services/xorg.scm
@@ -764,9 +764,10 @@ the GNOME desktop environment.")
 ;;;
 
 (define %gdm-accounts
-  (list (user-group (name "gdm") (system? #t))
+  (list (user-group (name "gdm") (system? #t) (id 900))
         (user-account
          (name "gdm")
+         (uid 900)
          (group "gdm")
          (system? #t)
          (comment "GNOME Display Manager user")