diff --git a/runtime/doc/usr_41.txt b/runtime/doc/usr_41.txt
index cef6fd7..f874b07 100644
--- a/runtime/doc/usr_41.txt
+++ b/runtime/doc/usr_41.txt
@@ -769,6 +769,7 @@
 	haslocaldir()		check if current window used |:lcd| or |:tcd|
 	tempname()		get the name of a temporary file
 	mkdir()			create a new directory
+	chdir()			change current working directory
 	delete()		delete a file
 	rename()		rename a file
 	system()		get the result of a shell command as a string