In a large skillet, cook beef, onion and green pepper over medium heat until meat is no longer pink; drain. Stir in soup and tomato sauce. Bring to a boil. Reduce heat; simmer, uncovered, for 10 minutes.
Meanwhile, cook macaroni according to package directions; drain.
In a greased 2-qt. baking dish, layer half of the macaroni, beef mixture and 1 cup cheese.
Repeat layers. Sprinkle with remaining cheese.
Bake, uncovered, at 350° for 25-30 minutes or until bubbly.