diff --git a/ceilometer/api/controllers/v2.py b/ceilometer/api/controllers/v2.py
index db81ad1314..164ff3a95e 100644
--- a/ceilometer/api/controllers/v2.py
+++ b/ceilometer/api/controllers/v2.py
@@ -88,6 +88,17 @@ class EntityNotFound(ClientSideError):
             status_code=404)
 
 
+class AlarmNotFound(ClientSideError):
+    def __init__(self, alarm, auth_project):
+        if not auth_project:
+            msg = _('Alarm %s not found') % alarm
+        else:
+            msg = _('Alarm %(alarm_id)s not found in project %'
+                    '(project)s') % {
+                        'alarm_id': alarm, 'project': auth_project}
+        super(AlarmNotFound, self).__init__(msg, status_code=404)
+
+
 class AdvEnum(wtypes.wsproperty):
     """Handle default and mandatory for wtypes.Enum."""
     def __init__(self, name, *args, **kwargs):
@@ -1767,7 +1778,7 @@ class Alarm(_Base):
                 alarms = list(pecan.request.storage_conn.get_alarms(
                     alarm_id=id, project=project))
                 if not alarms:
-                    raise EntityNotFound(_('Alarm'), id)
+                    raise AlarmNotFound(id, project)
 
         tc_names = [tc.name for tc in alarm.time_constraints]
         if len(tc_names) > len(set(tc_names)):
@@ -1881,7 +1892,7 @@ class AlarmController(rest.RestController):
         alarms = list(self.conn.get_alarms(alarm_id=self._id,
                                            project=auth_project))
         if not alarms:
-            raise EntityNotFound(_('Alarm'), self._id)
+            raise AlarmNotFound(alarm=self._id, auth_project=auth_project)
         return alarms[0]
 
     def _record_change(self, data, now, on_behalf_of=None, type=None):
diff --git a/ceilometer/tests/api/v2/test_alarm_scenarios.py b/ceilometer/tests/api/v2/test_alarm_scenarios.py
index 70575341da..9d2525a40b 100644
--- a/ceilometer/tests/api/v2/test_alarm_scenarios.py
+++ b/ceilometer/tests/api/v2/test_alarm_scenarios.py
@@ -234,7 +234,7 @@ class TestAlarms(v2.FunctionalTest,
     def test_get_not_existing_alarm(self):
         resp = self.get_json('/alarms/alarm-id-3', expect_errors=True)
         self.assertEqual(404, resp.status_code)
-        self.assertEqual("Alarm alarm-id-3 Not Found",
+        self.assertEqual('Alarm alarm-id-3 not found',
                          jsonutils.loads(resp.body)['error_message']
                          ['faultstring'])
 
@@ -1088,7 +1088,9 @@ class TestAlarms(v2.FunctionalTest,
                               'X-Project-Id': str(uuid.uuid4())}
         resp = self.post_json('/alarms', params=json, status=404,
                               headers=an_other_user_auth)
-        self.assertEqual("Alarm a Not Found",
+        self.assertEqual("Alarm a not found in project "
+                         "%s" %
+                         an_other_user_auth['X-Project-Id'],
                          jsonutils.loads(resp.body)['error_message']
                          ['faultstring'])
 
@@ -1121,7 +1123,8 @@ class TestAlarms(v2.FunctionalTest,
         headers['X-Roles'] = 'admin'
         resp = self.post_json('/alarms', params=json, status=404,
                               headers=headers)
-        self.assertEqual("Alarm a Not Found",
+        self.assertEqual("Alarm a not found in project "
+                         "aprojectidthatisnotmine",
                          jsonutils.loads(resp.body)['error_message']
                          ['faultstring'])
 
diff --git a/ceilometer/tests/api/v2/test_app.py b/ceilometer/tests/api/v2/test_app.py
index b98898efca..dafc39d237 100644
--- a/ceilometer/tests/api/v2/test_app.py
+++ b/ceilometer/tests/api/v2/test_app.py
@@ -213,12 +213,12 @@ class TestApiMiddleware(v2.FunctionalTest):
     def test_translated_then_untranslated_error(self):
         resp = self.get_json('/alarms/alarm-id-3', expect_errors=True)
         self.assertEqual(404, resp.status_code)
-        self.assertEqual("Alarm alarm-id-3 Not Found",
+        self.assertEqual("Alarm alarm-id-3 not found",
                          json.loads(resp.body)['error_message']
                          ['faultstring'])
 
         with mock.patch('ceilometer.api.controllers.'
-                        'v2.EntityNotFound') as CustomErrorClass:
+                        'v2.AlarmNotFound') as CustomErrorClass:
             CustomErrorClass.return_value = wsme.exc.ClientSideError(
                 "untranslated_error", status_code=404)
             resp = self.get_json('/alarms/alarm-id-5', expect_errors=True)