diff --git a/tempest/lib/services/compute/servers_client.py b/tempest/lib/services/compute/servers_client.py
index a687137..b49a250 100644
--- a/tempest/lib/services/compute/servers_client.py
+++ b/tempest/lib/services/compute/servers_client.py
@@ -209,6 +209,9 @@
                                post_body)
         if body:
             body = json.loads(body)
+        else:
+            if isinstance(body, bytes):
+                body = body.decode('utf-8')
         self.validate_response(schema, resp, body)
         return rest_client.ResponseBody(resp, body)