In mixing bowl toss together gingersnap crumbs, graham cracker crumbs, melted butter or margarine, and sugar.
Turn crumb mixture into a 9-inch pie plate.
Spread the crumb mixture evenly in the pie plate.
Press onto bottom and sides to form a firm, even crust.
Bake in 375° oven for 4 to 5 minutes.
Cool thoroughly on rack.