diff --git a/runtime/doc/if_pyth.txt b/runtime/doc/if_pyth.txt
index d37bd49..7bd9b37 100644
--- a/runtime/doc/if_pyth.txt
+++ b/runtime/doc/if_pyth.txt
@@ -180,6 +180,13 @@
 	Like |strwidth()|: returns number of display cells str occupies, tab 
 	is counted as one cell.
 
+vim.chdir(*args, **kwargs)				*python-chdir*
+vim.fchdir(*args, **kwargs)				*python-fchdir*
+	Run os.chdir or os.fchdir, then all appropriate vim stuff.
+	Note: you should not use these functions directly, use os.chdir and 
+	      os.fchdir instead. Behavior of vim.fchdir is undefined in case 
+	      os.fchdir does not exist.
+
 Error object of the "vim" module
 
 vim.error						*python-error*