Using current monoclonal antibody technology one can now produce a humanized antibody to virtually any target antigen that can be identified. Consequently, one would expect there to be more approved monoclonal antibody products. Inadequate product development at both the preclinical and clinical stages has contributed to the overall lack of success. This article discusses some of the obstacles to successful product development and offers suggestions to overcoming them. The key to monoclonal antibody development, as with other biological products, is understanding the properties of the product itself, to have some proof of concept before embarking on clinical studies, and to adequately design and power the pivotal trial.