diff --git a/gapic/templates/%namespace/%name_%version/%sub/services/%service/transports/rest.py.j2 b/gapic/templates/%namespace/%name_%version/%sub/services/%service/transports/rest.py.j2
index 060e5d0744..1341571e48 100644
--- a/gapic/templates/%namespace/%name_%version/%sub/services/%service/transports/rest.py.j2
+++ b/gapic/templates/%namespace/%name_%version/%sub/services/%service/transports/rest.py.j2
@@ -198,7 +198,7 @@ class {{ service.name }}RestTransport({{ service.name }}Transport):
         {% if not method.void %}response = {% endif %}self._session.{{ method.http_opt['verb'] }}(
             url
             {%- if 'body' in method.http_opt %},
-            json=body,
+            data=body,
             {%- endif %}
         )