This is what I use (in my /etc/procmailrc), but your mileage may vary: :0 { BOGOFILTER_DIR=/var/procmail :0fw | /usr/local/bin/bogofilter -f -e -p -l -c /var/procmail/bogo } /var/procmail/bogofilter.cf ( cut the filename short here so it would fit on one line) is the bogofilter config file.