diff --git a/tempest/services/compute/v3/json/flavors_client.py b/tempest/services/compute/v3/json/flavors_client.py
index f8c762c..739c870 100644
--- a/tempest/services/compute/v3/json/flavors_client.py
+++ b/tempest/services/compute/v3/json/flavors_client.py
@@ -63,7 +63,7 @@
         if kwargs.get('swap'):
             post_body['swap'] = kwargs.get('swap')
         if kwargs.get('rxtx'):
-            post_body['rxtx_factor'] = kwargs.get('rxtx')
+            post_body['os-flavor-rxtx:rxtx_factor'] = kwargs.get('rxtx')
         if kwargs.get('is_public'):
             post_body['flavor-access:is_public'] = kwargs.get('is_public')
         post_body = json.dumps({'flavor': post_body})