Deriving electrical energy from glucose and other carbohydrates under mild conditions is in important research objective because these biomolecules are abundant, renewable, have high energy density, and are convenient as fuels. This rich promise has not been realized because stable, inexpensive, and efficient catalysts are not available to oxidize carbohydrates and transfer all or nearly all of their electrons to fuel cell,modes. We report here that viologen catalysts meet these demanding Criteria by catalytically oxidizing glucose and other carbohydrates in it mildly alkaline solution, making possible a direct carbohydrate fuel cell. Formate and carbonate are major products of carbohydrate oxidation, demonstrating that extensive carbon-carbon bond breaking has occurred. A rudimentary fuel Cell utilizing viologen catalysts and glucose or dihydroxyacetone as fuels demonstrated electrical power production at up to 20 mA/cm(2) superficial current density. Improved catalyst function and cell design should significantly advance the efficiency and viability of direct carbohydrate fuel cell technology as a means of generating electrical energy from renewable biomass. (C) 2009 The Electrochemical Society. [DOI: 10.1149/1.3183815] All rights reserved.