Directed methanol fuel cells (DMFCs) are fabricated on printed circuit board (PCB) substrates by means of a photolithography process. The effects of channel pattern, channel width and methanol flow rate on the performance of the fabricated DMFC are evaluated over a range of flow-channel widths from 200 to 400 mu m and flow rates of methanol from 2 to 80 ml min(-1). A micro-DMFC with a cross-stripe channel pattern gives superior performance compared with zig-zag and serpentine type of pattern. A single cell with a 200-mu m wide channel delivers a maximum power density of 33 mW cm(-2) when using 2 M methanol feed at 80 degrees C. An air-breathing multi-DMFC composed of eight single unit cells gave 180 mW cm(-2) by using a methanol reservoir. It is considered that this may be the first reported attempt to develop a multi-DMFC with micro-channels fabricated on a PCB substrate. (c) 2006 Elsevier B.V. All rights reserved.