diff --git a/magit.el b/magit.el
index 886ac9ea..fab162f1 100644
--- a/magit.el
+++ b/magit.el
@@ -2164,7 +2164,7 @@ Prefix arg means justify as well."
 	(save-excursion
 	  (set-buffer buf)
 	  (goto-char (point-min))
-	  (while (looking-at "^\\([A-Za-z0-9]+\\): *\\(.*\\)$")
+	  (while (looking-at "^\\([A-Za-z0-9-_]+\\): *\\(.*\\)$")
 	    (setq result (acons (intern (downcase (match-string 1)))
 				(match-string 2)
 				result))
@@ -2178,7 +2178,7 @@ Prefix arg means justify as well."
     (save-excursion
       (set-buffer buf)
       (goto-char (point-min))
-      (if (search-forward-regexp (format "^\\([A-Za-z0-9]+:.*\n\\)+%s"
+      (if (search-forward-regexp (format "^\\([A-Za-z0-9-_]+:.*\n\\)+%s"
 					 (regexp-quote magit-log-header-end))
 				 nil t)
 	  (delete-region (match-beginning 0) (match-end 0)))