McDonald's introduced the Big Mac hamburger in 1967.
The sandwich was created by franchisee Jim Delligatti, who operated several McDonald's restaurants in the Pittsburgh area. It used two beef patties, a middle bun layer, lettuce, cheese, pickles, onions, and a special sauce, making it larger and more elaborate than the standard hamburger.
The Big Mac was first introduced in the Pittsburgh area in 1967 and became available nationally in the United States the following year. Its name and distinctive stacked construction turned it into a major product brand within McDonald's broader identity.
The Big Mac is sometimes dated to 1968 because that was the year of national availability. The product itself debuted regionally in 1967, which is the key date for its introduction.