Recent laboratory findings in rat models and on human urogenital tissues suggest that erythropoietin may play a role in protection of the cavernous nerves during surgery. Some degree of nerve trauma occurs during bilateral nerve-sparing radical prostatectomy, but for most it is temporary. Erythropoietin will be studied as an investigational drug for enhancement of erectile function postoperatively in a prospective, randomized study. Erythropoietin has been used in many men undergoing open radical prostatectomy in the past according to FDA indications for preparation for noncardiac, nonvascular surgery with a high risk of blood loss. Evidence also suggests it is safe with no demonstration of increased risk of venous thromboembolism (blood clots) or cardiac events for men with prostate cancer undergoing radical prostatectomy.