diff --git a/NEWS b/NEWS
index ed513a47..0e83c781 100644
--- a/NEWS
+++ b/NEWS
@@ -49,6 +49,7 @@ shadow-4.1.2.2 -> shadow-4.1.3						UNRELEASED
   * audit logging improvements.
   * error handling improvement (see above).
   * Speedup (see "addition of users or groups" above).
+  * do not create groups with GID set to (gid_t)-1.
 - groupdel
   * audit logging improvements.
   * error handling improvement (see above).
@@ -67,13 +68,20 @@ shadow-4.1.2.2 -> shadow-4.1.3						UNRELEASED
 - groupmod
   * audit logging improvements.
   * error handling improvement (see above).
+  * do not create groups with GID set to (gid_t)-1.
+- grpck
+  * warn for groups with GID set to (gid_t)-1.
 - newusers
   * Implement the -r, --system option.
   * Speedup (see "addition of users or groups" above).
+  * do not create users with UID set to (gid_t)-1.
+  * do not create groups with GID set to (gid_t)-1.
 - passwd
   * For compatibility with other passwd version, the --lock an --unlock
     options do not lock or unlock the user account anymore.  They only
     lock or unlock the user's password.
+- pwck
+  * warn for users with UID set to (uid_t)-1.
 - su
   * 
 - useradd
@@ -81,11 +89,13 @@ shadow-4.1.2.2 -> shadow-4.1.3						UNRELEASED
   * Speedup (see "addition of users or groups" above).
   * See CREATE_HOME above.
   * New -M/--no-create-home option to disable CREATE_HOME.
+  * do not create users with UID set to (gid_t)-1.
 - userdel
   * audit logging improvements.
 - usermod
   * Allow adding LDAP users (or any user not present in the local passwd
     file) to local groups
+  * do not create users with UID set to (gid_t)-1.
 
 shadow-4.1.2.1 -> shadow-4.1.2.2					23-11-2008
 
diff --git a/src/grpck.c b/src/grpck.c
index 877d2b3d..da23710b 100644
--- a/src/grpck.c
+++ b/src/grpck.c
@@ -3,7 +3,7 @@
  * Copyright (c) 1996 - 2000, Marek Michałkiewicz
  * Copyright (c) 2001       , Michał Moskal
  * Copyright (c) 2001 - 2006, Tomasz Kłoczko
- * Copyright (c) 2007 - 2008, Nicolas François
+ * Copyright (c) 2007 - 2009, Nicolas François
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -542,6 +542,14 @@ static void check_grp_file (int *errors, bool *changed)
 			printf (_("invalid group name '%s'\n"), grp->gr_name);
 		}
 
+		/*
+		 * Check for invalid user ID.
+		 */
+		if (grp->gr_gid == (gid_t)-1) {
+			printf (_("invalid user ID '%lu'\n"), grp->gr_gid);
+			*errors += 1;
+		}
+
 		/*
 		 * Workaround for a NYS libc 5.3.12 bug on RedHat 4.2 -
 		 * groups with no members are returned as groups with one
diff --git a/src/pwck.c b/src/pwck.c
index cb695ae2..1d311882 100644
--- a/src/pwck.c
+++ b/src/pwck.c
@@ -3,7 +3,7 @@
  * Copyright (c) 1996 - 2000, Marek Michałkiewicz
  * Copyright (c) 2001       , Michał Moskal
  * Copyright (c) 2001 - 2006, Tomasz Kłoczko
- * Copyright (c) 2007 - 2008, Nicolas François
+ * Copyright (c) 2007 - 2009, Nicolas François
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -395,6 +395,14 @@ static void check_pw_file (int *errors, bool *changed)
 			*errors += 1;
 		}
 
+		/*
+		 * Check for invalid user ID.
+		 */
+		if (pwd->pw_uid == (uid_t)-1) {
+			printf (_("invalid user ID '%lu'\n"), pwd->pw_uid);
+			*errors += 1;
+		}
+
 		/*
 		 * Make sure the primary group exists
 		 */