Clinical interest has recently increased for the concept of testosterone replacement therapy (TRT) to ameliorate the signs and symptoms of low testosterone levels (ie, hypogonadism). Any history of prostate cancer has been traditionally considered as an absolute contraindication to TRT. Because there are many younger patients with improved survival rates and cure after having undergone radical prostatectomy, TRT is considered more frequently by urologists for prostate cancer patients who are biochemically and pathologically free of disease. The purpose of this communication is to review the literature, formulate general guidelines for TRT in prostate cancer patients, and identify areas of future research.