diff --git a/README.rst b/README.rst
index 68317566..b5e6d3ce 100644
--- a/README.rst
+++ b/README.rst
@@ -109,7 +109,7 @@ The command line client is self-documenting. Use the --help flag to access the u
       --no-auth, -N         Do not use authentication.
       --os-identity-api-version <identity-api-version>
                             Specify Identity API version to use. Defaults to
-                            env[OS_IDENTITY_API_VERSION] or 3.0.
+                            env[OS_IDENTITY_API_VERSION] or 3.
 
       --os-auth-url <auth-url>, -A <auth-url>
                             Defaults to env[OS_AUTH_URL].
@@ -180,4 +180,4 @@ The command line client is self-documenting. Use the --help flag to access the u
 * Bugs: http://bugs.launchpad.net/python-barbicanclient
 
 .. [1] Documentation in this link is currently incomplete. Please use the
-`devstack setup. <http://docs.openstack.org/developer/barbican/setup/devstack.html>`__
\ No newline at end of file
+`devstack setup. <http://docs.openstack.org/developer/barbican/setup/devstack.html>`__
diff --git a/barbicanclient/barbican.py b/barbicanclient/barbican.py
index e7f4d5f5..fc0b1e5b 100644
--- a/barbicanclient/barbican.py
+++ b/barbicanclient/barbican.py
@@ -34,7 +34,9 @@ from barbicanclient import client
 from barbicanclient import version
 
 
-_DEFAULT_IDENTITY_API_VERSION = '3.0'
+_DEFAULT_IDENTITY_API_VERSION = '3'
+_IDENTITY_API_VERSION_2 = ['2', '2.0']
+_IDENTITY_API_VERSION_3 = ['3']
 
 
 class Barbican(app.App):
@@ -125,10 +127,19 @@ class Barbican(app.App):
         kwargs = self.build_kwargs_based_on_version(args, api_version)
         kwargs.update(kwargs_dict)
 
-        if not api_version or api_version == _DEFAULT_IDENTITY_API_VERSION:
-            method = v3.Token if auth_type == 'token' else v3.Password
-        else:
+        if api_version in _IDENTITY_API_VERSION_2:
             method = v2.Token if auth_type == 'token' else v2.Password
+        else:
+            if not api_version or api_version not in _IDENTITY_API_VERSION_3:
+                self.stderr.write(
+                    "WARNING: The identity version <{0}> is not in supported "
+                    "versions <{1}>, falling back to <{2}>.".format(
+                        api_version,
+                        _IDENTITY_API_VERSION_2 + _IDENTITY_API_VERSION_3,
+                        _DEFAULT_IDENTITY_API_VERSION
+                    )
+                )
+            method = v3.Token if auth_type == 'token' else v3.Password
 
         auth = method(**kwargs)
 
@@ -217,7 +228,7 @@ class Barbican(app.App):
                             default=client.env('OS_IDENTITY_API_VERSION'),
                             help='Specify Identity API version to use. '
                             'Defaults to env[OS_IDENTITY_API_VERSION]'
-                            ' or 3.0.')
+                            ' or 3.')
         parser.add_argument('--os-auth-url', '-A',
                             metavar='<auth-url>',
                             default=client.env('OS_AUTH_URL'),
diff --git a/barbicanclient/tests/keystone_client_fixtures.py b/barbicanclient/tests/keystone_client_fixtures.py
index bf6e22a4..eb3de381 100644
--- a/barbicanclient/tests/keystone_client_fixtures.py
+++ b/barbicanclient/tests/keystone_client_fixtures.py
@@ -47,7 +47,7 @@ V3_MEDIA_TYPES = [{'base': 'application/json',
                   {'base': 'application/xml',
                    'type': 'application/vnd.openstack.identity-v3+xml'}]
 
-V3_VERSION = {'id': 'v3.0',
+V3_VERSION = {'id': 'v3',
               'links': [{'href': V3_URL, 'rel': 'self'}],
               'media-types': V3_MEDIA_TYPES,
               'status': 'stable',
diff --git a/functionaltests/cli/v1/behaviors/base_behaviors.py b/functionaltests/cli/v1/behaviors/base_behaviors.py
index a4e75fad..5ebdd7e1 100644
--- a/functionaltests/cli/v1/behaviors/base_behaviors.py
+++ b/functionaltests/cli/v1/behaviors/base_behaviors.py
@@ -57,7 +57,7 @@ class BaseBehaviors(object):
             arg_list.extend(
                 ['--os-project-domain-name',
                  CONF.keymanager.project_domain_name])
-            arg_list.extend(['--os-identity-api-version', '3.0'])
+            arg_list.extend(['--os-identity-api-version', '3'])
         else:
             arg_list.extend(['--os-auth-url', CONF.identity.uri])
             arg_list.extend(['--os-tenant-name', CONF.keymanager.project_name])