Prostate cancer (PCa), with its potentially long latency, generally late-age onset, and high prevalence, is an ideal target for risk reduction and disease prevention strategies. Treatment of the disease is currently associated with significant side effects and reduced quality of life. Encouraging results are emerging in PCa risk reduction with 5α-reductase inhibitors (5-ARIs). The pivotal Prostate Cancer Prevention Trial (PCPT) with finasteride established the efficacy of 5-ARIs in reducing the period prevalence of PCa. Ongoing trials that will further clarify the role of 5-ARIs in preventing and treating PCa include the Reduction by Dutasteride of Prostate Cancer Events (REDUCE) with dutasteride in PCa risk reduction; the Reduction by Dutasteride of Clinical Progression Events in Expectant Management (REDEEM) trial on the effect of dutasteride on disease progression in low-grade localized PCa; and the Therapeutic Assessment of Rising PSAs [prostate-specific antigens] (TARP) trial on dutasteride in asymptomatic recurrent cancer. The data from these trials might initiate a paradigm shift in the attitudes of clinicians, healthcare policymakers, and patients to the benefits of PCa risk reduction strategies and their potential effect on a patient's health and quality of life.