Ultrahigh-molecular-weight polyethylene/ copper (UHMWPE/Cu) composites compatibilized with polyethylene-graft-maleic anhydride (PE-g-MAH) were prepared by compression molding. The effects of the compatibilizer on the mechanical, thermal, and tribological properties of the UHMWPE/Cu composites were investigated. These properties of the composites were evaluated at various compositions, and worn steel surfaces and composite surfaces were examined with scanning electron microscopy and X-ray photoelectron spectroscopy. The incorporation of PE-g-MAH reduced the melting points of the composites and increased their crystallinity to some extent. Moreover, the inclusion of the PE-g-MAH compatibilizer greatly increased the tensile rupture strength and tensile modulus of the composites, and thus improved the wear resistance of the composites. These improvements in the mechanical and tribological behavior of the ultrahigh-molecular-weight-poly-ethylene-matrix composites with the PE-g-MAH compatibilizer could be closely related to the enhanced crosslinking function of the composites in the presence of the compatibilizer. Moreover, the compatibilizer had an effect on the transfer and oxidation behavior of the filler Cu particulates, which could be critical to the application of metallic-particulate-filled polymer composites in engineering. (C) 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 948-955, 2004.