Hormonal manipulation represents an attractive therapeutic approach to patients with symptomatic benign prostatic hyperplasia (BPH). Antiandrogenic therapies have been incompletely evaluated but appear to shrink the prostate by 30% to 40%. However, their effect on symptoms is uncertain. Antiestrogenic therapy is also theoretically possible, as estrogens may be synergistic with androgens in stimulating and maintaining prostatic growth. The physiologic rationale and the clinical data derived from evaluation of various forms of hormonal therapy for BPH are reviewed.