In medium skillet, brown ground beef with onions and bell pepper until beef is thoroughly cooked. Drain.
In 3 1/2- to 4-quart slow cooker, combine cooked ground beef mixture, tomatoes, tomato sauce, soup and taco seasoning mix; mix well.
Cover; cook on high setting for 30 minutes.
Stir in beans. Reduce heat to low setting; cover and cook an additional 4 to 5 hours or until thoroughly heated.