Composite powders of carbon nanotubes (CNTs) and aluminum in which the CNTs are homogeneously dispersed within the Al powder are prepared with an in situ method. Uniform Ni nanoparticles are scattered evenly on the surfaces of Al powders, followed by CNT synthesis through chemical vapor deposition. The hardness and tensile strength of the CNT(Ni)–Al matrix composites are improved compared to aluminum.