Porous Pt-M (M = Cu, Zn, Ni) nanoparticles (NPs) were obtained by reduction of [Pt(CH3NH2)4][PtCl4] and M(Ac)2 (or MCl2) with oleylamine under mild conditions. The porous Pt-Cu NPs exhibited superior catalytic activities over a Pt/Cu NP mixture and Cu NPs as references for CO oxidation processes.