diff --git a/lisp/org.el b/lisp/org.el
index 1c3dfe5..6792bed 100644
--- a/lisp/org.el
+++ b/lisp/org.el
@@ -5146,8 +5146,7 @@ Optional argument N means, put the headline into the Nth line of the window."
 ;;; Folding of blocks
 
 (defconst org-block-regexp
-
-  "^[ \t]*#\\+begin_\\([^ \n]+\\)\\(\\([^\n]+\\)\\)?\n\\([^\000]+?\\)#\\+end_\\1"
+  "^[ \t]*#\\+begin_\\([^ \n]+\\)\\(\\([^\n]+\\)\\)?\n\\([^\000]+?\\)#\\+end_\\1[ \t]?"
   "Regular expression for hiding blocks.")
 
 (defvar org-hide-block-overlays nil