Yttria-tetragonal zirconia polycrystals (Y-TZP) and magnesia-partially stabilized zirconia (Mg-PSZ) ceramics were implanted with ions of C or a combination of Ti + C using a metal vapour vacuum are (MEVVA) ion implanter. Wear and frictional characteristics of ion-implanted Y-TZP and Mg-PSZ ceramic plates against unimplanted TZP and PSZ pins were investigated using a pin-on-plate reciprocating rig under two levels of load of 1.2 and 2.0 N and an average velocity of 0.1 m s(-1). The effects of ion implantation on friction coefficients and wear rates have been explored by comparing the results with those of unimplanted self-mated zirconia ceramics. It was found that the friction coefficients of the Ti + C and C ion-implanted ceramics were lower than those of the unimplanted ceramics tested under the same conditions but the duration of low friction was short. The wear resistance of the C-implanted zirconia ceramics was significantly higher during the first 400-600 m of sliding (4 X 10(4)-6 X 10(4) cycles) than that of the unmodified ceramics, especially at a lower load of 1.3 N. Ti + C ion implantation reduced the wear of TZP only slightly and did not affect the wear of PSZ ceramics due to a quite rapid removal of the implanted layer. The C-implanted layer persisted on the ceramic surfaces over a much longer sliding distance. (C) 2000 Published by Elsevier Science S.A.