diff --git a/nova/objects/instance.py b/nova/objects/instance.py
index 485732e267c7..c9208c96b59b 100644
--- a/nova/objects/instance.py
+++ b/nova/objects/instance.py
@@ -246,7 +246,7 @@ class Instance(base.NovaObject):
             instance_info_cache.InstanceInfoCache._from_db_object(
                     context, instance['info_cache'], db_inst['info_cache'])
         if ('security_groups' in expected_attrs and
-                db_inst.get('security_groups')):
+                db_inst.get('security_groups') is not None):
             instance['security_groups'] = security_group.SecurityGroupList()
             security_group._make_secgroup_list(context,
                                                instance['security_groups'],
diff --git a/nova/tests/objects/test_instance.py b/nova/tests/objects/test_instance.py
index b887471288a2..40d03eb75e69 100644
--- a/nova/tests/objects/test_instance.py
+++ b/nova/tests/objects/test_instance.py
@@ -375,6 +375,17 @@ class _TestInstanceObject(object):
         inst.save()
         self.assertEqual(inst.security_groups.obj_what_changed(), set())
 
+    def test_with_empty_security_groups(self):
+        ctxt = context.get_admin_context()
+        fake_inst = dict(self.fake_instance, security_groups=[])
+        fake_uuid = fake_inst['uuid']
+        self.mox.StubOutWithMock(db, 'instance_get_by_uuid')
+        db.instance_get_by_uuid(ctxt, fake_uuid, columns_to_join=[]
+                                ).AndReturn(fake_inst)
+        self.mox.ReplayAll()
+        inst = instance.Instance.get_by_uuid(ctxt, fake_uuid)
+        self.assertEqual(0, len(inst.security_groups))
+
     def test_with_fault(self):
         ctxt = context.get_admin_context()
         fake_inst = dict(self.fake_instance)