Carbon nanotubes (CNTs)/epoxy resin composites were prepared by using a sonication technique. Microstructure, mechanical and physical properties such as hardness, wear resistance, tensile strength and density of the composite samples were examined. The tensile strength of the 0.6 vol.% CNTs/epoxy resin composites compared with the monolithic epoxy resin increased 183%. The hardness and wear resistance were maximum at 0.8 vol.% CNTs. Moreover, SEM image of the composites indicated that there is good adhesion between CNTs and the epoxy resin.