A passive (air breathing) planar three-cell direct methanol fuel cell was designed, fabricated and tested. The design concepts for plates, current collectors, seals and membrane electrode assemblies are discussed in this paper. Testing of single cells and stacks with parallel and serial connections were carried out. The results show that a reliable areal power density of 8.6 mW cm(-2) can be achieved at ambient temperature with passive operation. Stacks with a serial connection of the single cells gave significantly higher performance than a parallel connection. It was also identified that high electrical resistance was the dominant factor in reducing performance. The major causes of the high resistance were the stainless steel hardware used and poor contact between the electrode and current collector. Future work will involve material and design studies of current collectors and seals to minimize the electrical resistance, and architectural design studies to effectively utilize the heat generated to raise operation temperature. (c) 2006 Elsevier B.V. All rights reserved.