Objective: To provide the first comprehensive assessment of the number of men exposed to continuous androgen deprivation therapy (ADT) in the nonmetastatic setting in the United States. Methods: We assembled 2 point-prevalent cohorts on December 31, 2008: men aged 18-64 years enrolled in commercial health plans (MarketScan) and men aged ≥67 years enrolled in fee-for-service (FFS) Medicare (Medicare 5% sample). We identified men with nonmetastatic prostate cancer who were actively receiving continuous ADT (gonadotropin-releasing hormone agonists or bilateral orchiectomy) for at least 6 months on the point-prevalence date. The number of prevalent ADT users in the national commercially insured (45-64 years) and FFS Medicare (≥65 years) populations was extrapolated with person-level weights. Using age-specific prevalence estimates derived from the 2 data sources, the number of prevalent users in the entire U.S. male population aged ≥45 years was also estimated. Results: We estimate that 11,935 commercially insured men aged 45-64 years (95% confidence interval [CI], 11,310-12,561) and 115,468 FFS Medicare male beneficiaries aged ≥65 years (95% CI, 112,304-118,633) represented patients with nonmetastatic prostate cancer actively receiving continuous ADT for ≥6 months in the United States on December 31, 2008. Extrapolated to the total U.S. male population aged ≥45 years, this estimate was 188,916 (95% CI, 184,104-193,727). Conclusion: Our findings suggest that a substantial number of men with nonmetastatic prostate cancer are managed with continuous ADT for ≥6 months during the course of their disease.