show-whitespace-mode.el is a simple mode to highlight whitespaces. To use load it with autoload or require an enter the following in the mini-buffer:

 M-x show-whitespace-mode RET

You can also add the function turn-on-show-whitespace-mode to any major mode hook. E.g. for the sgml-mode type:

 (add-hook 'sgml-mode-hook 'turn-on-show-whitespace-mode)

This doesn’t work anymore. The latest version of show-wspace.el seems broken --RyanDavis

You seem to be confusing show-whitespace-mode.el with show-wspace.el. That works in show-wspace.el, AFAICT. See ShowWhiteSpace. – DrewAdams

A recent version of show-whitespace-mode.el can be found here:


See ShowWhiteSpace for more alternatives.