diff --git a/ChangeLog b/ChangeLog
index 04379b6..0f18ee1 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2022  Yann Herklotz  <git@ymhg.org>
+
+	* unreleased:
+
+	(org): Add modified date which can be added on a before-save-hook.
+
 2022-05-03  Yann Herklotz  <git@ymhg.org>
 
 	* v0.5.0: Add date stamps to org-zettelkasten entries.
diff --git a/org-zettelkasten.el b/org-zettelkasten.el
index a5c364c..6b39342 100644
--- a/org-zettelkasten.el
+++ b/org-zettelkasten.el
@@ -113,6 +113,12 @@ NEWHEADING: function used to create the heading and set the current
         (org-zettelkasten-create-next)
       (org-zettelkasten-create-branch))))
 
+(defun org-zettelkasten-update-modified ()
+  "Update the modified timestamp, which can be done on save."
+  (interactive)
+  (org-set-property "modified" (format-time-string
+                                (org-time-stamp-format t t))))
+
 (defvar org-zettelkasten-mode-map
   (let ((map (make-sparse-keymap)))
     (define-key map "n" #'org-zettelkasten-create-dwim)