Many experimental studies of microbial fuel cells (MFCs) have been performed. MFC modeling, however, has not been adequately explored. We are aware of only one publication, in which a relatively simple model was used to simulate current production by bacteria employing an exogenous electron-transfer mediator. In this research, a model was developed to simulate power production by bacteria employing a direct or wire-like electron transfer strategy. The model considers a thin layer of bacteria on the anode that consume substrate and transfer electrons to the anode via wire-like connections. The effects of resistance of these connections and of the external circuit on power production are addressed. To verify the model, simulated sustainable power curves were compared with experimental results. The model successfully reproduced experimental trends, suggesting that the key processes are captured in the model.