Spread 1/2 cup spaghetti sauce in a lightly greased 13"x9" baking dish; layer with half the ravioli. Pour 1 1/4 cups sauce over ravioli; top with one cup cottage cheese and 2 cups mozzarella cheese.
Repeat layers; sprinkle with Parmesan cheese. Bake, uncovered, at 350° for 40 minutes. Let stand 10 minutes before serving.