McDonald’s french fries were introduced in 1949. They became a defining part of the chain’s menu after the McDonald brothers’ restaurant system made a small, fast-cooked menu central to American roadside dining.
The fries were originally cooked in a mixture of 93% beef tallow and 7% cottonseed oil, a formula that produced a distinctive savory flavor and crisp texture. That detail is often confused with the later history of McDonald’s frying oil: the company eventually moved away from beef tallow, and modern formulations differ by market and time period.
The 1949 date refers to the introduction of McDonald’s fries, not the founding of the restaurant business itself. The McDonald brothers opened their original restaurant in San Bernardino in 1940, then rebuilt it around a streamlined service model in 1948. Fries replaced potato chips on the menu in 1949, helping establish the thin, uniform style now associated with the brand.
Frozen fries became important later, especially as McDonald’s expanded and sought consistent cooking across many locations.