In this paper, two-dimensional steady-state and dynamic models for an enzymatic fuel cell are developed. The anode consists of a biocatalyst (an enzyme cascade of glucose dehydrogenase and diaphorase with VK3 mediator) immobilized in a porous electrically-conducting anode, while glucose and the phosphate buffer are supplied from a solution. An air-breathing bilirubin oxidase/ferricyanide cathode and a cellophane membrane complete the cell unit. Detailed mass and charge balances are combined with a model for the reaction mechanism in the electrodes. The model is validated against experimental polarization data, demonstrating good agreement, and the dynamic performance is discussed. The VK3 equilibrium potential is varied and its effect on the enzymatic system and power output is examined. (C) 2013 The Electrochemical Society. All rights reserved.