In the present investigation, the sliding wear behavior is described for Al2O3/ZrO2 micro/nanocomposites and monolithic alumina of similar grain size under defined conditions of a constant sliding speed and different loads (20-150 N). Nano ZrO2 particles (1.7 vol%) were observed uniformly distributing throughout the composites, and most of them were located within the matrix alumina grains. The wear rate of the alumina and the micro/nanocomposites increased as the contact load increased and a clear transition in friction and wear behavior was observed in both materials. However, the nanocomposite wear resistance at low contact loads was one order of magnitude higher than that of the alumina. In the severe regime, no difference was observed among the materials. The low wear rate (10(-7) mm(3).(N.m)(-1)) along with low pullout indicates higher wear resistance of micro/nanocomposites in the mild regime compared with monolithic alumina. Based on the morphological observation of worn surfaces by scanning electron microscope and on residual stress analysis performed by neutron diffraction, some wear mechanisms of Al2O3-ZrO2 micro/nanocomposites are proposed. The high wear resistance of the nanocomposites is discussed in terms of fracture resistance properties and residual stress. Improvements in mechanical and tribological properties of these composites make them promising candidates for biomedical applications.