I probably wouldn't use filters to do this. In my experience it is uncommon for genuine spam to come from the same sender more than once. Blacklisting that sender simply doesn't make sense if that address will never be used again. Filters can be useful to screen out certain text appearing in the subject or in some case the message text, though of course spammers go out of their way to make this hard. Is this truly Spam, otherwise known as UCE? Some users seem to think that anything they don't want to read is "spam", and often it may be stuff that they have effectively signed up for and have become bored with. I get a lot of newsletters and circulars which are not of any great interest, but they are not spam. I call them "cruft" and filter them accordingly, but in these cases I know the senders and so can filter on sender addresses. There are a few annoying cases where they use different randomised strings for different campaigns, so they don't have a single static "from" address. However, you can build a second filter using "ends with" to detect messages from specific domains. If you have a general nuisance filter then it makes more sense to copy the offending email address (right click is your friend) and then edit the existing filter and add the new email address. Make sure you have the "Match '''any '''of the following" option selected. Do train your Junk Controls by marking unwanted stuff as Junk. It does not take immediate effect, but over time it becomes very accurate. Likewise, if it incorrectly marks good messages as Junk, mark them as Not Junk, so it learns what you do and don't like.