Wear tests were performed with a Mg-PSZ/stavax couple using a strip-on-disk configuration. The centre sliding velocity was 1·4 m/s, the normal pressures used were 0·09 MPa, 0·13 MPa and 0·23 MPa and the testing times were 20 h, 70 h and 200 h. Tests were done under ambient conditions and with water as a lubricant. Polished as well as ground Mg-PSZ surfaces were used. The strength of the Mg-PSZ, the surface roughness of the Mg-PSZ and the wear volumes of the Mg-PSZ and the stavax were measured. The worn surfaces of the Mg-PSZ were examined with optical microscopy using interference contrast and with scanning electron microscopy. The strength of the material was found to be independent of testing time. It was concluded that the influence of the mechanical and/or thermal interaction between the Mg-PSZ and the steel on the residual stress layer was the strength-determining factor. Testing under ambient conditions caused more residual stress and thus a higher strength than testing with water as a lubricant. The relation between wear volume Wv and time t could be described by Wv = c1t and the relation between wear volume and load P by Wv = c2(P - Pc). The Ra of worn surfaces was found to be independent of normal pressure. A wear mechanism, incorporating adhesion of the stavax on the Mg-PSZ and delamination of the Mg-PSZ, was derived from observations of the worn surfaces and of the wear debris.