Sift together flour, baking powder, soda, and salt in a medium mixing bowl. Cut shortening into flour mixture with a pastry blender until mixture resembles coarse meal. Add buttermilk; stirring until dry ingredients are moistened.
Drop dough by tablespoonfuls 1 1/2 inches apart onto greased baking sheets. Bake at 450° for 10 minutes or until biscuits are lightly browned.