diff --git a/cinderclient/tests/v1/fakes.py b/cinderclient/tests/v1/fakes.py
index 6520da651..16b725a13 100644
--- a/cinderclient/tests/v1/fakes.py
+++ b/cinderclient/tests/v1/fakes.py
@@ -321,6 +321,7 @@ class FakeHTTPClient(base_client.HTTPClient):
         action = list(body)[0]
         if action == 'os-attach':
             assert sorted(list(body[action])) == ['instance_uuid',
+                                                  'mode',
                                                   'mountpoint']
         elif action == 'os-detach':
             assert body[action] is None
diff --git a/cinderclient/tests/v1/test_volumes.py b/cinderclient/tests/v1/test_volumes.py
index f38fbe6fb..33c62e313 100644
--- a/cinderclient/tests/v1/test_volumes.py
+++ b/cinderclient/tests/v1/test_volumes.py
@@ -35,7 +35,7 @@ class VolumesTest(utils.TestCase):
 
     def test_attach(self):
         v = cs.volumes.get('1234')
-        cs.volumes.attach(v, 1, '/dev/vdc')
+        cs.volumes.attach(v, 1, '/dev/vdc', mode='rw')
         cs.assert_called('POST', '/volumes/1234/action')
 
     def test_detach(self):
diff --git a/cinderclient/tests/v2/fakes.py b/cinderclient/tests/v2/fakes.py
index 53bb35890..891787f1f 100644
--- a/cinderclient/tests/v2/fakes.py
+++ b/cinderclient/tests/v2/fakes.py
@@ -328,6 +328,7 @@ class FakeHTTPClient(base_client.HTTPClient):
         action = list(body)[0]
         if action == 'os-attach':
             assert sorted(list(body[action])) == ['instance_uuid',
+                                                  'mode',
                                                   'mountpoint']
         elif action == 'os-detach':
             assert body[action] is None
diff --git a/cinderclient/tests/v2/test_volumes.py b/cinderclient/tests/v2/test_volumes.py
index 7e44f840b..4e3a8afd4 100644
--- a/cinderclient/tests/v2/test_volumes.py
+++ b/cinderclient/tests/v2/test_volumes.py
@@ -38,7 +38,7 @@ class VolumesTest(utils.TestCase):
 
     def test_attach(self):
         v = cs.volumes.get('1234')
-        cs.volumes.attach(v, 1, '/dev/vdc')
+        cs.volumes.attach(v, 1, '/dev/vdc', mode='ro')
         cs.assert_called('POST', '/volumes/1234/action')
 
     def test_detach(self):
diff --git a/cinderclient/v1/volumes.py b/cinderclient/v1/volumes.py
index 36758c7b0..dbff995ac 100644
--- a/cinderclient/v1/volumes.py
+++ b/cinderclient/v1/volumes.py
@@ -38,13 +38,14 @@ class Volume(base.Resource):
         """Update the display_name or display_description for this volume."""
         self.manager.update(self, **kwargs)
 
-    def attach(self, instance_uuid, mountpoint):
+    def attach(self, instance_uuid, mountpoint, mode='rw'):
         """Set attachment metadata.
 
         :param instance_uuid: uuid of the attaching instance.
         :param mountpoint: mountpoint on the attaching instance.
+        :param mode: the access mode
         """
-        return self.manager.attach(self, instance_uuid, mountpoint)
+        return self.manager.attach(self, instance_uuid, mountpoint, mode)
 
     def detach(self):
         """Clear attachment metadata."""
@@ -240,7 +241,7 @@ class VolumeManager(base.ManagerWithFind):
         url = '/volumes/%s/action' % base.getid(volume)
         return self.api.client.post(url, body=body)
 
-    def attach(self, volume, instance_uuid, mountpoint):
+    def attach(self, volume, instance_uuid, mountpoint, mode='rw'):
         """
         Set attachment metadata.
 
@@ -248,11 +249,13 @@ class VolumeManager(base.ManagerWithFind):
                        you would like to attach.
         :param instance_uuid: uuid of the attaching instance.
         :param mountpoint: mountpoint on the attaching instance.
+        :param mode: the access mode.
         """
         return self._action('os-attach',
                             volume,
                             {'instance_uuid': instance_uuid,
-                             'mountpoint': mountpoint})
+                             'mountpoint': mountpoint,
+                             'mode': mode})
 
     def detach(self, volume):
         """
diff --git a/cinderclient/v2/volumes.py b/cinderclient/v2/volumes.py
index e6dae9704..bd5c2680c 100644
--- a/cinderclient/v2/volumes.py
+++ b/cinderclient/v2/volumes.py
@@ -37,13 +37,14 @@ class Volume(base.Resource):
         """Update the name or description for this volume."""
         self.manager.update(self, **kwargs)
 
-    def attach(self, instance_uuid, mountpoint):
+    def attach(self, instance_uuid, mountpoint, mode='rw'):
         """Set attachment metadata.
 
         :param instance_uuid: uuid of the attaching instance.
         :param mountpoint: mountpoint on the attaching instance.
+        :param mode: the access mode.
         """
-        return self.manager.attach(self, instance_uuid, mountpoint)
+        return self.manager.attach(self, instance_uuid, mountpoint, mode)
 
     def detach(self):
         """Clear attachment metadata."""
@@ -233,18 +234,20 @@ class VolumeManager(base.ManagerWithFind):
         url = '/volumes/%s/action' % base.getid(volume)
         return self.api.client.post(url, body=body)
 
-    def attach(self, volume, instance_uuid, mountpoint):
+    def attach(self, volume, instance_uuid, mountpoint, mode='rw'):
         """Set attachment metadata.
 
         :param volume: The :class:`Volume` (or its ID)
                        you would like to attach.
         :param instance_uuid: uuid of the attaching instance.
         :param mountpoint: mountpoint on the attaching instance.
+        :param mode: the access mode.
         """
         return self._action('os-attach',
                             volume,
                             {'instance_uuid': instance_uuid,
-                             'mountpoint': mountpoint})
+                             'mountpoint': mountpoint,
+                             'mode': mode})
 
     def detach(self, volume):
         """Clear attachment metadata.