The McDonald's breakfast sandwich introduced in 1971 was the Egg McMuffin.
The Egg McMuffin was created by McDonald's franchisee Herb Peterson and introduced in 1971. It used an English muffin, a round egg, Canadian bacon, and cheese, creating a portable breakfast product that could be prepared and served consistently in restaurants.
Its importance to branding history goes beyond the sandwich itself. The Egg McMuffin helped McDonald's establish breakfast as a major daypart and gave the company a signature product outside its traditional hamburger menu. Breakfast advertising, including the later Birdie the Early Bird character, built on this expansion.
The sandwich is sometimes confused with the McGriddle, which arrived much later and uses griddle cakes. The Filet-O-Fish and Big Mac are also major McDonald's products, but neither is the 1971 breakfast item that helped define the chain's morning identity.