The use of recombinant DNA methods to produce large quantities of protein for therapeutic uses has revolutionized medicine. Industrial challenges for manufacture of biotherapeutic proteins are related to the characteristics of these proteins and the increasing quantities required to address needs of patients, worldwide. A brief overview of therapies in which proteins are employed helps to frame some of the challenges facing their industrial production. The number of molecules and their applications have significantly expanded over the last 15-20 years, together with the quantities used to address specific indications. Challenges addressed include achieving cell density, protein expression, separations of cells and protein, protein purification, and segmentation of protein production into smaller quantities with the evolution of personalized medicine and products designed for increasingly small patient populations. This chapter highlights some of the current challenges.