There is a progression over time of relevant measurable benign prostatic hyperplasia (BPH) end points including symptoms, flow rates, prostate size, complications such as acute urinary retention (AUR), and surgical rates. Only two classes of medical therapy, the alpha-blockers and a 5-alpha-reductase inhibitor, have shown unequivocal and consistent efficacy over placebo in 1-year studies. Both of these classes of medications have demonstrated relative long-term safety. Finasteride has been shown in three large, 2-year, randomized, controlled studies to be superior to placebo, and both finasteride and the alpha-blockers have demonstrated long-term efficacy and safety in open-label studies. The efficacy of finasteride is significantly enhanced when it is used in patients with large prostates. Long-term finasteride therapy also results in a significant reduction in the incidence of AUR and the need for surgery. Long-term medical therapy for BPH is effective and safe. Data are now available that allow clinicians to analyze the long-term risks and benefits of the various medical options and subsequently rationalize long-term therapy for individual patients.