Chemical process design generally is a multi-objective optimization problem with conflicting objectives. It can be solved efficiently by calculating the Pareto frontier, the set of Pareto-optimal compromises. Multi-objective optimization and decision support techniques have been implemented in the BASF in-house process simulation software CHEMASIM. The Pareto frontier is calculated automatically and an innovative slider concept is used to navigate the results and to support the decision making by the designer. The software is a valuable contribution to the process design work flow.