Turning machinability of aluminum alloy composites reinforced with carbon bers was examined using a carbide tool. Pitch-based short carbon ber was used as the reinforcement. The composites were fabricated by squeeze casting. Optical microscopy revealed that the bers were randomly arranged in the alloy matrix. The ber reinforcement decreased the hardness of the alloy. The ber reinforcement also decreased the cutting resistance of the aluminum alloy, and the resistance values of the composite was lower than that of a composite reinforced with short alumina bers. The roughness of the machined surface was signi cantly decreased by the ber reinforcement under every cutting condition. No carbide tool wear was observed even if the composite underwent a machining of 2 km, whereas the tool wear was clearly observed for the alumina ber-reinforced composite. These results indicated that the carbon bers in the alloy act as a solid lubricant. Chips formed by machining the composite were powdery, whereas the chips formed by machining the unreinforced aluminum alloy was long.