diff --git a/Doc/library/json.rst b/Doc/library/json.rst
index 433f948..f652039 100644
--- a/Doc/library/json.rst
+++ b/Doc/library/json.rst
@@ -328,6 +328,8 @@
    those with character codes in the 0-31 range, including ``'\t'`` (tab),
    ``'\n'``, ``'\r'`` and ``'\0'``.
 
+   If the data being deserialized is not a valid JSON document, a
+   :exc:`ValueError` will be raised.
 
    .. method:: decode(s)