Using makefile-fill-paragraph on text in which some lines fit precisely within the fill-column will fill past the fill-column. The problem stems from the direct use of fill-paragraph-function followed by makefile-backslash-region, which inserts more text on each line. I think this can be solved by decrementing fill-column before invoking fill-paragraph-function, and I've included a patch to that effect. Thanks, Kirk --- make-mode.el 2010-08-20 16:51:46.253395990 -0400 +++ make-mode-patch.el 2010-08-20 16:53:08.985392193 -0400 @@ -1323,7 +1323,9 @@ (save-restriction (narrow-to-region beginning end) (makefile-backslash-region (point-min) (point-max) t) - (let ((fill-paragraph-function nil)) + (let ((fill-paragraph-function nil) + ;; adjust fill-column to allow space for the backslash + (fill-column (- fill-column 1))) (fill-paragraph nil)) (makefile-backslash-region (point-min) (point-max) nil) (goto-char (point-max))