A wet chemical assembling process has been developed for the formation of the anode electrocatalyst layers of a microtubular direct methanol fuel cell (DMFC). By using this method, a porous layer of PtRu electrocatalyst was bonded onto the inner surface of a tubular polymer electrolyte membrane by chemical reduction of Pt and Ru complexes impregnated in the membrane. The characteristic parameters such as catalyst loading amount and composition of PtRu were optimized by using a half-cell testing method. A novel heat treatment process was further carried out for enhancing the performance of the obtained PtRu electrocatalyst. The microtubular DMFC with a 2.8 mg-PtRu cm(-2) anode exhibited a peak power density of 1.8 mW cm(-2) under passive and air breathing conditions at ambient temperature and pressure. (c) 2005 The Electrochemical Society. [DOI: 10.1149/1.2131822] All rights reserved.