A microfluidic fuel cell is defined as a fuel cell with fluid delivery and removal, reaction sites and electrode structures all confined to a microfluidic channel. Microfluidic fuel cells typically operate in a co-laminar now configuration Without a physical barrier, Such as a membrane, to separate the anode and the cathode. This review article summarizes the development of microfluidic fuel cell technology, from the invention in 2002 until present, with emphasis on theory, fabrication, unit cell development, performance achievements, design considerations, and scale-up options. The main challenges associated with the current status of the technology are provided along with suggested directions for further research and development, Moreover, microfluidic fuel cell architectures show great potential for integration with biofuel cell technology. This review therefore includes microfluidic biofuel cell developments to date and presents opportunities for future work in this multi-disciplinary field. (c) 2008 Elsevier B.V. All rights reserved.