diff --git a/Documentation/git-am.txt b/Documentation/git-am.txt
index f7d551e2c7..77ef103b21 100644
--- a/Documentation/git-am.txt
+++ b/Documentation/git-am.txt
@@ -21,6 +21,10 @@ current branch.
 
 OPTIONS
 -------
+<mbox>...::
+	The list of mailbox files to read patches from. If you do not
+	supply this argument, reads from the standard input.
+
 --signoff::
 	Add `Signed-off-by:` line to the commit message, using
 	the committer identity of yourself.