Wet-chemical assembling process has been developed for the formation of the anode electrocatalyst layers of a micro tubular direct formic acid fuel cell. By using this method, a porous layer of Pd nano-catalyst was bonded onto the inner surface of a tubular polymer electrolyte membrane by chemical reduction of Pd complex impregnated in the membrane. The performance characteristics as a function of parameters such as catalyst loading amount of Pd or the cell temperature were evaluated by using a half-cell testing method. The micro tubular DFAFC with a 2.5 mg-Pd cm(-2) anode and 6 mg-Pt cm(-2) cathode fabricated by wholly wet-chemical assembling process exhibited a peak power density over 4 mW cm(-2) under passive and air breathing conditions at ambient temperature and pressure. (C) 2007 Elsevier Ltd. All rights reserved.