The major focus of the current fuel cell industry is on reduction of cost and weight of the fuel cell stack for its commercial application. Usage of machined bipolar plates has the disadvantage of high cost of machining, weight, volume, etc. This paper discusses the use of sheet metallic bipolar plates (flow fields), with parallel hemispherical channels design. Single cell stack consisting of sheet metal bipolar plates with 16cm(2) active area is tested and was observed to show excellent performance as compared to the conventionally machined parallel flow field design with the same active area. Maximum current density of about 7000 A m(-2) and power density of about 1500 W m(-2) was achieved. Long-term stability test of the stack at open circuit potential and constant load (1A) for 100 h showed no detrimental effects on its performance. Substantial saving on weight and cost of the stack using sheet metal bipolar plates was also observed. (c) 2006 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.