Abstract: Carbon nanotubes (WMNTs)/epoxy resin nanocomposites were prepared making use of ultrasonic dispersion and casting molding. The influence of the MWNTs on the friction and wear behaviors of the resulting nanocomposites sliding against AISI-1045 steel was investigated on an Optimol-SRV tribotester at ambient condition. The worn surface morphologies of the composites were observed on a scanning electron microscope. It was found that the incorporation of the MWNTs contributed to greatly increase the friction-reducing and antiwear abilities of the WMNTs/EP composites. Moreover, the MWNTs/EP composite prepared in the presence of ultrasonic dispersion with a larger power had better friction-reducing and antiwear abilities than that prepared with the ultrasonic dispersion of a smaller power, which was attributed to the different dispersion uniformity of the WMNTs in the resin matrix thereat. The epoxy resin was dominated by adhesion fatigue peeling off and severe plastic deformation as it slid against the steel, while the adhesion and plastic deformation were considerably abated for the nanocomposites under the same test conditions, which was attributed to the strengthening and self-lubricating functions of the WMNTs.