diff --git a/docs/user/quickstart.rst b/docs/user/quickstart.rst
index 6829d592..1a2c6fbf 100644
--- a/docs/user/quickstart.rst
+++ b/docs/user/quickstart.rst
@@ -281,6 +281,7 @@ the ``json`` parameter (added in version 2.4.2) and it will be encoded automatic
 
     >>> r = requests.post(url, json=payload)
 
+Note, the ``json`` parameter is ignored if either ``data`` or ``files`` is passed.
 
 POST a Multipart-Encoded File
 -----------------------------