diff --git a/beets/autotag/match.py b/beets/autotag/match.py
index db90481ff..58d40bbd6 100644
--- a/beets/autotag/match.py
+++ b/beets/autotag/match.py
@@ -192,8 +192,10 @@ def assign_items(items, tracks):
 
     # Produce the output matching.
     mapping = dict((items[i], tracks[j]) for (i, j) in matching)
-    extra_items = set(items) - set(mapping.keys())
-    extra_tracks = set(tracks) - set(mapping.values())
+    extra_items = list(set(items) - set(mapping.keys()))
+    extra_items.sort(key=lambda i: (i.disc, i.track, i.title))
+    extra_tracks = list(set(tracks) - set(mapping.values()))
+    extra_tracks.sort(key=lambda t: (t.index, t.title))
     return mapping, extra_items, extra_tracks
 
 def track_index_changed(item, track_info):
diff --git a/test/test_autotag.py b/test/test_autotag.py
index 43c2f2ce5..11e7c7f46 100644
--- a/test/test_autotag.py
+++ b/test/test_autotag.py
@@ -409,8 +409,8 @@ class AssignmentTest(unittest.TestCase):
         trackinfo.append(TrackInfo(u'three', None))
         mapping, extra_items, extra_tracks = \
             match.assign_items(items, trackinfo)
-        self.assertEqual(extra_items, set())
-        self.assertEqual(extra_tracks, set())
+        self.assertEqual(extra_items, [])
+        self.assertEqual(extra_tracks, [])
         self.assertEqual(mapping, {
             items[0]: trackinfo[0],
             items[1]: trackinfo[2],
@@ -428,8 +428,8 @@ class AssignmentTest(unittest.TestCase):
         trackinfo.append(TrackInfo(u'three', None))
         mapping, extra_items, extra_tracks = \
             match.assign_items(items, trackinfo)
-        self.assertEqual(extra_items, set())
-        self.assertEqual(extra_tracks, set())
+        self.assertEqual(extra_items, [])
+        self.assertEqual(extra_tracks, [])
         self.assertEqual(mapping, {
             items[0]: trackinfo[0],
             items[1]: trackinfo[2],
@@ -446,8 +446,8 @@ class AssignmentTest(unittest.TestCase):
         trackinfo.append(TrackInfo(u'three', None))
         mapping, extra_items, extra_tracks = \
             match.assign_items(items, trackinfo)
-        self.assertEqual(extra_items, set())
-        self.assertEqual(extra_tracks, set([trackinfo[1]]))
+        self.assertEqual(extra_items, [])
+        self.assertEqual(extra_tracks, [[trackinfo[1]]])
         self.assertEqual(mapping, {
             items[0]: trackinfo[0],
             items[1]: trackinfo[2],
@@ -463,8 +463,8 @@ class AssignmentTest(unittest.TestCase):
         trackinfo.append(TrackInfo(u'three', None))
         mapping, extra_items, extra_tracks = \
             match.assign_items(items, trackinfo)
-        self.assertEqual(extra_items, set([items[1]]))
-        self.assertEqual(extra_tracks, set())
+        self.assertEqual(extra_items, [[items[1]]])
+        self.assertEqual(extra_tracks, [])
         self.assertEqual(mapping, {
             items[0]: trackinfo[0],
             items[2]: trackinfo[1],
@@ -513,8 +513,8 @@ class AssignmentTest(unittest.TestCase):
 
         mapping, extra_items, extra_tracks = \
             match.assign_items(items, trackinfo)
-        self.assertEqual(extra_items, set())
-        self.assertEqual(extra_tracks, set())
+        self.assertEqual(extra_items, [])
+        self.assertEqual(extra_tracks, [])
         for item, info in mapping.iteritems():
             self.assertEqual(items.index(item), trackinfo.index(info))