diff --git a/pandora_client/__init__.py b/pandora_client/__init__.py
index 1eb3ecf..21b5dfc 100755
--- a/pandora_client/__init__.py
+++ b/pandora_client/__init__.py
@@ -1164,7 +1164,7 @@ class API(ox.API):
                     form['done'] = '1'
                 form['offset'] = str(done)
                 files = [
-                    ('file', (fname, chunk, mimetype))
+                    ('chunk', (fname, chunk, mimetype))
                 ]
                 try:
                     data = self._json_request(uploadUrl, form, files)