Machairodus was a genus of large machairodontine sabre-toothed cats that lived in North America during the Miocene to Pleistocene, existing for approximately 11.5 million years.

It was about 1.2 m at the shoulder, according to skeletal and life reconstructions.If accurate, this would make it one of the largest felids. The skull of Machairodus was noticeably narrow compared with the skulls of modern pantherine big cats, and the orbits were relatively small. The canines were long, thin and flattened from side to side but broad from front to back like the blade of a knife, as in Homotherium. The front and back edges of the canines were serrated when they first grew, but these serrations were worn down in the first few years of the animal's life.

A single fossil specimen was determined to have an approximate body mass of 201.8 kg.

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