In a large bowl, combine the ground beef with the bread crumbs, beaten egg, 1/2 cup of ketchup, mustard, onion and peppers, salt, pepper, and oregano. Mix until thoroughly blended.
Pack the beef mixture into a meatloaf pan or a 9-by-5-by-3-inch loaf pan.
Bake the meatloaf for 1 hour. Spread the remaining 1/4 cup of ketchup over the loaf and bake for about 10 to 15 minutes longer. The meatloaf is ready when it reaches 160 F (165 F if there is poultry in the meat mixture).