In this work a model-based method is proposed for determining the optimal set points for the leavening process in a continuous bread-making industrial plant. The procedure is based on a model of the leavening process, which has been identified using Neural Networks and ARX models. A Genetic Algorithm has been used to derive the optimal production set points, taking into account economic constraints. Two modes of operation of the plant have been investigated and optimized results have been confirmed by experiments on an industrial plant. (C) 2003 Elsevier Ltd. All rights reserved.