diff --git a/tools/emacs/lammps-mode.el b/tools/emacs/lammps-mode.el
index 9dfd119d0a..9ba2669982 100644
--- a/tools/emacs/lammps-mode.el
+++ b/tools/emacs/lammps-mode.el
@@ -242,12 +242,5 @@
   (setq lammps-comment-regexp nil)
   (setq lammps-variable-regexp nil))
 
-;; apply it to specified filename patterns
-(setq auto-mode-alist
- (append auto-mode-alist
-  '(("in\\." . lammps-mode))
-  '(("\\.lmp\\'" . lammps-mode))
-  ))
-
 (provide 'lammps-mode)
 ;;; lammps-mode.el ends here