The scale-up and commercialization of biological products is a difficult task that requires collaboration of scientists and engineers from various disciplines. Computer-aided process synthesis and analysis tools can facilitate this task by introducing a common language of communication among the various research and development groups and by providing a total systems approach. BioPro Designer is such a software design tool that runs on personal computers and features an interactive and user friendly interface. This paper presents the architecture and the important features of BioPro Designer.