diff --git a/h2o-py/h2o/connection.py b/h2o-py/h2o/connection.py
index <HASH>..<HASH> 100644
--- a/h2o-py/h2o/connection.py
+++ b/h2o-py/h2o/connection.py
@@ -491,6 +491,7 @@ class H2OConnection(object):
         files = {file_upload_info["file"] : open(file_upload_info["file"], "rb")}
         return requests.post(url, files=files, headers=headers)
       elif method == "POST":
+        headers["Content-Type"] = "application/x-www-form-urlencoded"
         return requests.post(url, data=post_body, headers=headers)
       elif method == "DELETE":
         return requests.delete(url, headers=headers)
Set Content-Type: application/x-www-form-urlencoded for regular POST requests.