diff --git a/nova/api/ec2/cloud.py b/nova/api/ec2/cloud.py
index a27057aa7821..aa7e880dfea1 100644
--- a/nova/api/ec2/cloud.py
+++ b/nova/api/ec2/cloud.py
@@ -987,7 +987,7 @@ class CloudController(object):
             # TODO(yamahata): volume attach time
             ebs = {'volumeId': volume_id,
                    'deleteOnTermination': bdm['delete_on_termination'],
-                   'attachTime': vol['attach_time'] or '-',
+                   'attachTime': vol['attach_time'] or '',
                    'status': vol['status'], }
             res = {'deviceName': bdm['device_name'],
                    'ebs': ebs, }
diff --git a/nova/db/sqlalchemy/api.py b/nova/db/sqlalchemy/api.py
index 9c4e1a85d2ce..bd3c94d80123 100644
--- a/nova/db/sqlalchemy/api.py
+++ b/nova/db/sqlalchemy/api.py
@@ -2981,6 +2981,7 @@ def volume_detached(context, volume_id):
         volume_ref['mountpoint'] = None
         volume_ref['attach_status'] = 'detached'
         volume_ref['instance_uuid'] = None
+        volume_ref['attach_time'] = None
         volume_ref.save(session=session)
 
 
diff --git a/nova/tests/api/ec2/test_cloud.py b/nova/tests/api/ec2/test_cloud.py
index 459c17143dc4..62690ee85978 100644
--- a/nova/tests/api/ec2/test_cloud.py
+++ b/nova/tests/api/ec2/test_cloud.py
@@ -2065,12 +2065,14 @@ class CloudTestCase(test.TestCase):
         self.assertEqual(vol['mountpoint'], mountpoint)
         self.assertEqual(vol['status'], "in-use")
         self.assertEqual(vol['attach_status'], "attached")
+        self.assertNotEqual(vol['attach_time'], None)
 
     def _assert_volume_detached(self, vol):
         self.assertEqual(vol['instance_uuid'], None)
         self.assertEqual(vol['mountpoint'], None)
         self.assertEqual(vol['status'], "available")
         self.assertEqual(vol['attach_status'], "detached")
+        self.assertEqual(vol['attach_time'], None)
 
     def test_stop_start_with_volume(self):
         """Make sure run instance with block device mapping works"""
diff --git a/nova/tests/test_volume.py b/nova/tests/test_volume.py
index 0c5328456298..7b14d8a99bfc 100644
--- a/nova/tests/test_volume.py
+++ b/nova/tests/test_volume.py
@@ -273,6 +273,7 @@ class VolumeTestCase(test.TestCase):
         self.assertEqual(vol['attach_status'], "attached")
         self.assertEqual(vol['mountpoint'], mountpoint)
         self.assertEqual(vol['instance_uuid'], instance_uuid)
+        self.assertNotEqual(vol['attach_time'], None)
 
         self.assertRaises(exception.VolumeAttached,
                           self.volume.delete_volume,
@@ -286,6 +287,7 @@ class VolumeTestCase(test.TestCase):
                                        volume_id)
         vol = db.volume_get(self.context, volume_id)
         self.assertEqual(vol['status'], "available")
+        self.assertEqual(vol['attach_time'], None)
 
         self.volume.delete_volume(self.context, volume_id)
         self.assertRaises(exception.VolumeNotFound,