The wear behavior of Ti-based alloys was analyzed by considering the elastic-plastic fracture of individual alloys in response to the relevant contact stress field. Using the contact stresses as the process driving force, wear was computed as the wear rate or volume loss as a function of hardness and tensile ductility for Ti-based cast alloys containing an alpha, alpha+beta or beta microstructure with or without the intermetallic precipitates. Model predictions indicated that wear of Ti alloys increases with increasing hardness but with decreasing fracture toughness or tensile ductility. The theoretical results are compared with experimental data to elucidate the roles of microstructure in wear and contrasted against those in grindability.