diff --git a/lisp/net/dig.el b/lisp/net/dig.el
index ab199bd81c5..17de169e244 100644
--- a/lisp/net/dig.el
+++ b/lisp/net/dig.el
@@ -120,10 +120,6 @@ Buffer should contain output generated by `dig-invoke'."
       (setq str (replace-match "" nil nil str)))
     str))
 
-;; XEmacs does it like this.  For Emacs, we have to set the
-;; `font-lock-defaults' buffer-local variable.
-(put 'dig-mode 'font-lock-defaults '(dig-font-lock-keywords t))
-
 (defvar dig-mode-map
   (let ((map (make-sparse-keymap)))
     (define-key map "g" nil)