ABSTRACTTitanium and many of its alloys show very poor wear resistance considering their hardness. This together with high thermodynamic driving forces to form very hard compounds between titanium and nitrogen or carbon made titanium based alloys obvious candidates for ion implantation. In this paper the effects of similar implanted concentration profiles of nitrogen and carbon in two titanium alloys are compared. The wear behavior of pin on disk wear tests are reported along with the ultramicrohardness of the four samples.