This paper presents a multiobjective optimization model based on a mathematical programming formulation for the optimal planning of a biorefinery, considering the optimal selection of feedstock, processing technology, and a set of products. The multiobjective optimization problem simultaneously considers the profit maximization and the environmental impact minimization. The economic objective function takes into account the availability of bioresources, processing limits, and demand of products, as well as the costs of feedstocks, products, and processing routes. On the other hand, the environmental assessment includes the overall environmental impact measured through the eco-indicator-99 based on the life cycle analysis methodology. The proposed methodology generates a Pareto curve that identifies the set of optimal solutions for both objectives, and it is applied to a case study for planning the production of a biorefinery in Mexico.