Antitumor vaccines, also known as active immunotherapies, have become an intense focus of research over the last decade as a means to ideally provide new targeted, and less toxic, therapies to patients with a variety of malignancies. Prostate cancer is among the diseases where a large amount of promising data has been accumulating regarding several distinct active immunotherapies. Here the authors review one of the therapies, known as GVAX, which is among the furthest along in clinical evaluation. The authors review the preclinical studies leading to the development of this immunotherapy, describe the results from clinical trials conducted in patients with prostate cancer, and discuss the benefits, limitations and potential future applications of this technology.