In this work, the influences of heat treatments on the microstructural features and, consequently, on the mechanical and wear characteristics of Co-Cr-Mo-C alloys commonly used as hip and knee implant materials, are investigated. Specimens of Co-Cr-Mo-C alloy in the as-cast condition were solution treated at 1230 A degrees C for 3 h, and then either were quenched in water or furnace cooled. The achieved microstructures of the heat-treated samples, characterized by fine globular and lamellar-type carbides due to the different thermal-treatment conditions, was proved to affect the material microstructural, mechanical and wear behavior. The wear behavior was evaluated by means of pin-on-disk wear tests, which showed that the wear properties are strongly affected by the carbides shape, distribution, and size. It was proved that both large carbides precipitated in as-cast alloys, and also lamellar-type carbides induced by slow cooling after solubilization caused lower wear resistance than the globular fine carbides that were dispersed in the solution-treated and water-quenched specimens. Moreover, the epsilon-martensite, formed by the strain-induced martensitic transformation through plastic straining during the sliding of pin on disk, decreases the wear rate mainly due to the lower number of slip systems of the hexagonal structure.