Gather all ingredients.
Mix together graham cracker crumbs, confectioners' sugar, butter or margarine, and 1 cup peanut butter in a medium bowl until well-blended.
Press evenly into the bottom of an ungreased 9x13-inch pan.
Place chocolate chips and 4 tablespoons peanut butter in a microwave-safe bowl. Microwave on high, stirring every 15 seconds, until smooth.
Spread mixture over crust.
Refrigerate for at least 1 hour before cutting into 12 squares.