We forecast the health and budgetary impact of hepatitis C (HCV) treatment on the Medicare program based on currently observed rates of treatment among Medicare and non-Medicare patients and identify the impact of higher rates of treatment among non-Medicare populations. We developed a computer microsimulation model to conduct an epidemiologic forecast, a budgetary impact analysis, and a cost-effectiveness analysis of the treatment of HCV based on three scenarios: 1) no treatment, 2) continuation of current-treatment rates, and 3) treatment rates among non-Medicare patients increased to match that of Medicare patients. The simulated population is based on National Health and Nutrition Examination Survey data. HCV progression rates and costs were calculated in Surveillance, Epidemiology, and End Results Program Medicare 5% claims data from the Chronic Hepatitis Cohort Study and published literature. We estimate that 13.6% of patients with HCV in the United States are enrolled in Medicare, but 75% will enter Medicare in the next 20 years. Medicare patients were over 5 times as likely to be treated in 2014-2015 as other patients. Medicare paid over $9 billion in treatment costs in both 2015 and 2016 and will total $28.4 billion from 2017-2026. Increasing treatment rates among non-Medicare patients would lead to 234,000 more patients being treated, reduce HCV mortality by 19%, and decrease Medicare costs by $18.6 billion from 2017-2026. We find that treatment remains cost-effective under most assumptions, costing $31,718 per quality adjusted life year gained. Conclusion: Medicare treats a disproportionately large share of HCV patients. Continued low rates of treatment among non-Medicare HCV patients will result in both reduced and deferred treatment, shifting future treatment costs to Medicare while increasing overall medical management costs, morbidity, and mortality. (Hepatology Communications 2017;1:99-109).