Co-Cr-Mo(ASTM F75) alloy is normally used for hip and knee prostheses. In this study, the effects of heat treatments on the mechanical and corrosion properties of Co-Cr-Mo alloy were studied. Solid solution treatment was performed at 1230℃ for 2 h to increase the ductility of the as-cast alloy, and the alloy was aged 700℃ for 1 h to increase the strength. Tensile and corrosion tests were carried out in each heat-treated alloy. Chemical composition change and phase transformation were investigated by X-ray diffractometry(XRD) and energy dispersive spectroscopy (EDS). Morphologies of each as-cast and heat-treated alloy were observed by optical microscopy(OM) and scanning electron microscopy(SEM). Tensile strength and elongation of Co-Cr-Mo alloy were observed as 940 MPa and 18%, respectively, when the alloy was aged at 700℃ for 1 h after solid solution treatment and quenching. The mechanical properties of Co-Cr-Mo alloy were improved without retrogression of corrosion properties by solid solution treatment.