Nylon 1010 composite specimens were prepared with CuO filler and short carbon fiber (CF) as the reinforcement. Friction and wear behavior of composite materials was investigated in a ring-block wear tester. The results show that carbon fiber was more effective in reducing friction and wear of nylon than CuO filler. Nylon composite with 20% CF and 10% CuO content filler had the lowest wear rate that could not be obtained with any proportion of the fiber or the filler alone. It was found that the transfer film on the counterpart of 20% CF-10% CuO-nylon was thin, continuous, and uniform. These differences in tribological performance have been studied according to the synergism between the carbon fiber and CuO filler. The tribochemical studies by X-ray photoelectron spectroscopy (XPS) revealed that pure CU, Cu2O, and Cu(OH)(2) were produced due to the decomposition of CuO during sliding. Carbon fiber promoted the process of tribochemical reactions of CuO, which generated more pure Cu particle and then self-lubricating transfer film including pure Cu was formed on the steel counterpart. (C) 2003 Wiley Periodicals, Inc.