McDonald's added the Big Mac to its national menu in 1968.
The sandwich had been created by franchisee Jim Delligatti, who operated McDonald's restaurants in the Pittsburgh area. It used two beef patties, a middle bun layer, lettuce, cheese, pickles, onions, and Big Mac sauce.
The Big Mac became more than a menu item: its name, stacked construction, and distinctive sauce became major parts of McDonald's product branding. The sandwich was first sold regionally before the company made it available throughout the United States.
It is often confused with the Quarter Pounder, another famous McDonald's burger. The Quarter Pounder is defined by the weight of its beef patty before cooking, while the Big Mac is identified by its two-patty, three-bun design.