In a medium bowl, combine corned beef, cream cheese, Swiss cheese, sauerkraut, sour cream, ketchup and mustard. Spoon into a greased, 1-quart baking dish.
1/2 lb diced corned beef, 1 package (8 oz) cream cheese, softened, 1 cup shredded Swiss cheese, 1 cup sauerkraut, drained, 1/2 cup sour cream, 1 tbsp ketchup, 1 tbsp spicy brown mustard