The Egg McMuffin was McDonald's first nationally advertised breakfast sandwich, introduced in 1972.
Herb Peterson, a McDonald's franchise owner in Santa Barbara, California, created the sandwich in the early 1970s. Its English muffin, egg, Canadian bacon, and cheese offered a portable breakfast format that could be prepared quickly.
The product helped McDonald's build breakfast into a major part of its brand identity. Before its expansion, the chain was primarily associated with hamburgers, fries, and daytime meals.
The Egg McMuffin is often confused with the later Sausage McMuffin or with the broader McDonald's breakfast menu. The egg sandwich is the product credited with establishing the chain's nationally promoted breakfast business.