diff --git a/cinderclient/shell.py b/cinderclient/shell.py
index 536ec3c0a..3ff9277cf 100644
--- a/cinderclient/shell.py
+++ b/cinderclient/shell.py
@@ -138,7 +138,8 @@ class OpenStackCinderShell(object):
         parser.add_argument('--os-auth-system',
                             metavar='<os-auth-system>',
                             dest='os_auth_type',
-                            default=utils.env('OS_AUTH_SYSTEM'),
+                            default=(utils.env('OS_AUTH_TYPE') or
+                                     utils.env('OS_AUTH_SYSTEM')),
                             help=_('DEPRECATED! Use --os-auth-type. '
                                    'Defaults to env[OS_AUTH_SYSTEM].'))
         parser.add_argument('--os_auth_system',
@@ -146,7 +147,8 @@ class OpenStackCinderShell(object):
         parser.add_argument('--os-auth-type',
                             metavar='<os-auth-type>',
                             dest='os_auth_type',
-                            default=utils.env('OS_AUTH_TYPE'),
+                            default=(utils.env('OS_AUTH_TYPE') or
+                                     utils.env('OS_AUTH_SYSTEM')),
                             help=_('Defaults to env[OS_AUTH_TYPE].'))
         parser.add_argument('--os_auth_type',
                             help=argparse.SUPPRESS)
diff --git a/cinderclient/tests/unit/test_shell.py b/cinderclient/tests/unit/test_shell.py
index 728dfd42d..9930f58f9 100644
--- a/cinderclient/tests/unit/test_shell.py
+++ b/cinderclient/tests/unit/test_shell.py
@@ -72,6 +72,26 @@ class ShellTest(utils.TestCase):
 
         return out
 
+    def test_default_auth_env(self):
+        _shell = shell.OpenStackCinderShell()
+        args, __ = _shell.get_base_parser().parse_known_args([])
+        self.assertEqual('', args.os_auth_type)
+
+    def test_auth_type_env(self):
+        self.make_env(exclude='OS_PASSWORD',
+                      include={'OS_AUTH_SYSTEM': 'non existent auth',
+                               'OS_AUTH_TYPE': 'noauth'})
+        _shell = shell.OpenStackCinderShell()
+        args, __ = _shell.get_base_parser().parse_known_args([])
+        self.assertEqual('noauth', args.os_auth_type)
+
+    def test_auth_system_env(self):
+        self.make_env(exclude='OS_PASSWORD',
+                      include={'OS_AUTH_SYSTEM': 'noauth'})
+        _shell = shell.OpenStackCinderShell()
+        args, __ = _shell.get_base_parser().parse_known_args([])
+        self.assertEqual('noauth', args.os_auth_type)
+
     def test_help_unknown_command(self):
         self.assertRaises(exceptions.CommandError, self.shell, 'help foofoo')