In machining operations, achieving better surface roughness is one of the important goals, furthermore, composite materials are increasingly replacing conventional materials. But their machinability differs from metals, because of anisotropic properties of the composites. In this research, the influence of milling parameters (feed, cutting speed, depth of cut) on surface roughness of bidirectional carbon fiber reinforced composite was investigated. Measurements were performed on both parallel and perpendicular directions of feed motion. Taguchi experimental design was used to determine the optimum milling condition and the effective parameter on the surface roughness. The optimum condition was obtained with a cutting speed of 125 m x min(-1), a feed of 0.1 mm x rev(-1) and a depth of cut of 1.5 mm. In addition, the most effective parameter on the surface roughness of parallel direction (Ra-x) was found to be feed and that of perpendicular direction (Ra-y) was found to be cutting speed.