Alloying with transition elements is proven to be an effective way to improve the methanol electro-oxidation reaction (MOR) and oxygen reduction reaction (ORR) activities of Pt catalysts for direct methanol fuel cells (DMFCs). Through a process of rapid solidification and two-step dealloying, we have successfully fabricated three-dimensional mesoporous PtM (M = Co, Cu, Ni) nanowire catalysts, which show much enhanced electrocatalytic properties towards MOR and ORR in comparison with the commercial Pt/C catalyst. Electrochemical tests indicate that alloying with Cu presents the best ORR activities, the half-wave potential of which is 42 mV positively shifted compared with the commercial Pt/C (0.892 V vs. RHE). Meanwhile, the PtM nanowire catalysts also possess good CO tolerance as well as stability for 10 000 cycles of cyclic voltammetry scanning. This convenient preparation method is promising for the development of high performance electrocatalysts for MOR and ORR in DMFCs.