In a medium bowl, stir together graham cracker crumbs, confectioners' sugar, 1 cup peanut butter and melted butter. Press firmly into the bottom of a 9x13-inch pan.
Melt chocolate chips and remaining 1/4 cup peanut butter in the microwave, stirring occasionally. Spread melted chocolate over the crumb crust. Chill for one hour and then cut into squares.