diff --git a/include/extern.h b/include/extern.h
index 96fa68f13..43488aa24 100644
--- a/include/extern.h
+++ b/include/extern.h
@@ -600,6 +600,7 @@ extern void mon_arrive(struct monst *, int);
 extern void mon_catchup_elapsed_time(struct monst *, long);
 extern void keepdogs(boolean);
 extern void migrate_to_level(struct monst *, coordxy, coordxy, coord *);
+extern void discard_migrating_mons(void);
 extern int dogfood(struct monst *, struct obj *);
 extern boolean tamedog(struct monst *, struct obj *);
 extern void abuse_dog(struct monst *);
diff --git a/src/do.c b/src/do.c
index 8bb2aab5b..5daeecbd5 100644
--- a/src/do.c
+++ b/src/do.c
@@ -1463,6 +1463,8 @@ goto_level(
         /* mark #overview data for all dungeon branches as uninteresting */
         for (l_idx = 0; l_idx < g.n_dgns; ++l_idx)
             remdun_mapseen(l_idx);
+        /* get rid of monsters scheduled to migrate to discarded levels */
+        discard_migrating_mons();
     }
 
     if (Is_rogue_level(newlevel) || Is_rogue_level(&u.uz))
diff --git a/src/dog.c b/src/dog.c
index 064cbd1a5..a984f03db 100644
--- a/src/dog.c
+++ b/src/dog.c
@@ -843,6 +843,28 @@ migrate_to_level(
         vision_recalc(0);
 }
 
+/* when entering the endgame, levels from the dungeon and its branches are
+   discarded because they can't be reached again; do the same for monsters
+   scheduled to migrate to those levels */
+void
+discard_migrating_mons(void)
+{
+    struct monst *mtmp, **mprev;
+    d_level mdest;
+
+    for (mprev = &g.migrating_mons; (mtmp = *mprev) != 0; ) {
+        mdest.dnum = mtmp->mux;
+        mdest.dlevel = mtmp->muy;
+        /* the Wizard is kept regardless of location so that he is
+           ready to be brought back; nothing should be scheduled to
+           migrate to the endgame but if we find such, we'll keep it */
+        if (!mtmp->iswiz && !In_endgame(&mdest))
+            *mprev = mtmp->nmon; /* remove mtmp from migrating_mons */
+        else
+            mprev = &mtmp->nmon; /* keep mtmp on migrating_mons */
+    }
+}
+
 /* return quality of food; the lower the better */
 /* fungi will eat even tainted food */
 int