diff --git a/keystone/resource/core.py b/keystone/resource/core.py
index 542fff1873..f8d72e91e8 100644
--- a/keystone/resource/core.py
+++ b/keystone/resource/core.py
@@ -405,6 +405,8 @@ class Manager(manager.Manager):
             self._update_project_enabled_cascade(project_id, project_enabled)
 
         try:
+            project['is_domain'] = (project.get('is_domain') or
+                                    original_project['is_domain'])
             ret = self.driver.update_project(project_id, project)
         except exception.Conflict:
             raise exception.Conflict(
diff --git a/keystone/tests/unit/resource/test_core.py b/keystone/tests/unit/resource/test_core.py
index 4842cfc913..2eb87e4ca3 100644
--- a/keystone/tests/unit/resource/test_core.py
+++ b/keystone/tests/unit/resource/test_core.py
@@ -94,6 +94,27 @@ class TestResourceManagerNoFixtures(unit.SQLDriverOverrides, unit.TestCase):
         self.assertRaises(exception.UnexpectedError,
                           self.resource_api.ensure_default_domain_exists)
 
+    def test_update_project_name_conflict(self):
+        name = uuid.uuid4().hex
+        description = uuid.uuid4().hex
+        domain_attrs = {
+            'id': CONF.identity.default_domain_id,
+            'name': name,
+            'description': description,
+        }
+        domain = self.resource_api.create_domain(
+            CONF.identity.default_domain_id, domain_attrs)
+        project1 = unit.new_project_ref(domain_id=domain['id'],
+                                        name=uuid.uuid4().hex)
+        self.resource_api.create_project(project1['id'], project1)
+        project2 = unit.new_project_ref(domain_id=domain['id'],
+                                        name=uuid.uuid4().hex)
+        project = self.resource_api.create_project(project2['id'], project2)
+
+        self.assertRaises(exception.Conflict,
+                          self.resource_api.update_project,
+                          project['id'], {'name': project1['name']})
+
 
 class DomainConfigDriverTests(object):