diff --git a/tempest_lib/common/rest_client.py b/tempest_lib/common/rest_client.py
index 8aa1325..20d5744 100644
--- a/tempest_lib/common/rest_client.py
+++ b/tempest_lib/common/rest_client.py
@@ -15,13 +15,13 @@
 #    under the License.
 
 import collections
-import json
 import logging as real_logging
 import re
 import time
 
 import jsonschema
 from oslo_log import log as logging
+from oslo_serialization import jsonutils as json
 import six
 
 from tempest_lib.common import http
@@ -439,16 +439,9 @@ class RestClient(object):
             self._log_request_full(method, req_url, resp, secs, req_headers,
                                    req_body, resp_body, caller_name, extra)
 
-    def _json_loads(self, resp_body):
-        if isinstance(resp_body, bytes):
-            resp_body = json.loads(resp_body.decode('utf8'))
-        else:
-            resp_body = json.loads(resp_body)
-        return resp_body
-
     def _parse_resp(self, body):
         try:
-            body = self._json_loads(body)
+            body = json.loads(body)
         except ValueError:
             return body
 
diff --git a/tempest_lib/services/identity/v2/token_client.py b/tempest_lib/services/identity/v2/token_client.py
index 1e5b58e..d7575d4 100644
--- a/tempest_lib/services/identity/v2/token_client.py
+++ b/tempest_lib/services/identity/v2/token_client.py
@@ -12,9 +12,8 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
-import json
-
 from oslo_log import log as logging
+from oslo_serialization import jsonutils as json
 
 from tempest_lib.common import rest_client
 from tempest_lib import exceptions
@@ -88,13 +87,13 @@ class TokenClient(rest_client.RestClient):
         self._log_request(method, url, resp)
 
         if resp.status in [401, 403]:
-            resp_body = self._json_loads(resp_body)
+            resp_body = json.loads(resp_body)
             raise exceptions.Unauthorized(resp_body['error']['message'])
         elif resp.status not in [200, 201]:
             raise exceptions.IdentityError(
                 'Unexpected status code {0}'.format(resp.status))
 
-        return resp, self._json_loads(resp_body)
+        return resp, json.loads(resp_body)
 
     def get_token(self, user, password, tenant, auth_data=False):
         """Returns (token id, token data) for supplied credentials."""
diff --git a/tempest_lib/services/identity/v3/token_client.py b/tempest_lib/services/identity/v3/token_client.py
index 50dc21d..7798f20 100644
--- a/tempest_lib/services/identity/v3/token_client.py
+++ b/tempest_lib/services/identity/v3/token_client.py
@@ -12,9 +12,8 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
-import json
-
 from oslo_log import log as logging
+from oslo_serialization import jsonutils as json
 
 from tempest_lib.common import rest_client
 from tempest_lib import exceptions
@@ -138,13 +137,13 @@ class V3TokenClient(rest_client.RestClient):
         self._log_request(method, url, resp)
 
         if resp.status in [401, 403]:
-            resp_body = self._json_loads(resp_body)
+            resp_body = json.loads(resp_body)
             raise exceptions.Unauthorized(resp_body['error']['message'])
         elif resp.status not in [200, 201, 204]:
             raise exceptions.IdentityError(
                 'Unexpected status code {0}'.format(resp.status))
 
-        return resp, self._json_loads(resp_body)
+        return resp, json.loads(resp_body)
 
     def get_token(self, **kwargs):
         """Returns (token id, token data) for supplied credentials"""