Objectives Chronic hepatitis C virus (HCV) is a leading cause of hospitalization and death in populations coinfected with human immunodeficiency virus (HIV). Sofosbuvir (SOF) is a pan-genotypic drug that should be combined with other agents as an oral treatment for HCV. We performed a 5-year horizon budget impact analysis of SOF-based regimens for the management of HIV/HCV-coinfected patients. Methods A multicenter, prospective evaluation was conducted, involving four Italian Infectious Diseases Departments (Galliera, San Martino, Sanremo, and La Spezia). All 1,005 genotype-coinfected patients (30% cirrhotics) under observation were considered (patients in all disease-stages were considered: chronic hepatitis C, cirrhosis, transplant, hepatocellular carcinoma). Disease stage costs per patient were collected; the expected disease progression in the absence of treatment and sustained virological response (SVR) success rate for SOF-based regimens were calculated based on the literature and expert opinion. Drug prices were based on what the National Health Service paid for them. The comparison of “no treatment” disease progression costs versus the economic impact of SOF-based regimens was investigated. Results Over the following 5 years, the disease progression scenario resulted in direct costs of approximately €54 million. Assuming an SVR success rate of 90%, average SOF-based regimens cost up to €50,000 per person, resulting in a final cost of more than €56 million, so this option is not economically viable. At the average price of €12,000, SOF-based regimens, expense was €17 million, saving 68%. At this price level, the economic resources invested in treating mild to moderate fibrosis stage patients would be equal to the amount of direct costs of disease management in this stage, resulting in a valid return of investment in the short-term. Conclusion Given the high rates of SVR, in the Italian Healthcare System, SOF-based regimens, price is a determinant and a predictor of the overall cost for the Hepatitis C patient’s management. At the average price per therapy of €12,000 over the next 5 years, SOF-based regimens are becoming highly sustainable.