Nanoporous Pt-Co alloy nanowires were synthesized by electrodeposition of Co-rich Pt(1)Co(99) alloy into anodic aluminum oxide (AAO) membranes, followed by a dealloying treatment in a mild acidic medium. These nanowires consist of porous skeletons with tiny pores of 1-5 nm and crystalline ligaments of 2-8 nm. Morphological and compositional evolutions of the porous Pt-Co nanowires upon dealloying were investigated, and their formation mechanism is discussed. The nanoporous Pt-Co alloy nanowires are found to exhibit distinctly enhanced electrocatalytic activities toward methanol oxidation as compared to the current state-of-the-art Pt/C and PtCo/C catalysts, thus showing substantial promise as efficient anode electrocatalysts in direct methanol fuel cells.