Yes they do!
Pathmark does take competitor and internet coupons. It says so right in their circular.
So, if you find a great coupon at Walgreens, CVS, Target or any of your local grocery stores, see if you can match up a sale with them at Pathmark.
Right now Pathmark has 50% Perdue and $1.99/lb ground beef. Match that up with this great $5 off $25 meat coupon from Stop & Shop and you have got yourself a great deal.