Biochemical reactors are essential unit operations in a wide variety of biotechnological processes. As compared to conventional chemical reactors, bioreactors present unique modeling and control challenges due to the complexity of the underlying biochemical reactions and the heterogenous nature of cell populations. The dynamic behavior of bioreactors can be strongly affected by variations between individual cells that are captured only with cell population models. This paper is intended to highlight our recent work on dynamic modeling and feedback control of yeast cell populations in continuous bioreactors. The results presented demonstrate the feasibility of using cell population models as the basis for dynamic analysis and model-based control of continuous yeast bioreactors. The paper concludes with a short discussion of future research needs in this challenging area. (C) 2003 Elsevier Science Ltd. All rights reserved.