Many types of nonsurgical therapy, including balloon dilation, hyperthermia, adrenergic blockade, and hormonal therapy, have been used for the treatment of benign prostatic hyperplasia (BPH). Antiandrogen therapy has been the most extensively studied form of hormonal treatment for BPH, although estrogens, antiestrogens, and antiprolactin agents have also been used (Scott and Coffey: Vitam Horm 33:439-465, 1975). The theoretical basis of antiandrogen therapy will be reviewed along with a summary of relevant clinical trials. Recent advances in the development of agents that more selectively inhibit the androgen-dependent growth of the prostate will be presented.