diff --git a/lisp/org.el b/lisp/org.el
index 6f7a2c7ef..680086df2 100644
--- a/lisp/org.el
+++ b/lisp/org.el
@@ -25032,7 +25032,8 @@ when non-nil, is a regexp matching keywords names."
   "Produce the index for Imenu."
   (dolist (x org-imenu-markers) (move-marker x nil))
   (setq org-imenu-markers nil)
-  (let* ((n org-imenu-depth)
+  (let* ((case-fold-search nil)
+	 (n org-imenu-depth)
 	 (re (concat "^" (org-get-limited-outline-regexp)))
 	 (subs (make-vector (1+ n) nil))
 	 (last-level 0)