diff --git a/Doc/library/os.rst b/Doc/library/os.rst
index d70f403e8cf1f3..2f7b37019e4a43 100644
--- a/Doc/library/os.rst
+++ b/Doc/library/os.rst
@@ -1909,7 +1909,8 @@ features:
 
    Create a directory named *path* with numeric mode *mode*.
 
-   If the directory already exists, :exc:`FileExistsError` is raised.
+   If the directory already exists, :exc:`FileExistsError` is raised. If a parent
+   directory in the path does not exist, :exc:`FileNotFoundError` is raised.
 
    .. _mkdir_modebits: