OBJECTIVES: to assess the impact, on the budget of the Brazilian HIV ARV National Program, of the introduction of darunavir/ritonavir(DRV/r)800/100 mg once a day as an optional protease inhibitor(PI) in the 2^nd-line regimen after failure to at least 1 PI and as a substitute 3^rd-line therapy for patients treating with DRV 600 mg twice a day, without POWER mutations. METHODS: We performed a 5-years budget impact analysis based on the 3 line regimens proposed by the 2013-Brazilian HIV treatment guideline comparing two scenarios:(1)DRV800 included in the guideline;(2)DRV800 not included. Model inputs:patients/line estimation considered prevalence, diagnosis, patients under treatment, mortality, treatment failure, and frequency of POWER mutations. Epidemiological data was obtained from national reports and clinical data from literature review. Dosing was based on current treatment national guideline and treatment data based on real world data from survey conducted by Close-Up. Treatment line costs(Brazilian Reais – BRL)=regimen costs weighted by frequency of use. Government prices=based on current acquisition costs from MoH purchases. DRV800 is under regulatory review. DRV800 price=assumed to be the same of DRV600 paid by the MoH(0.016/mg). RESULTS: Over the next 5 years, if the MoH reach its 90-90-90 target, the expected number of patient under HIV therapy will increase from 410,321 to 669,952. The introduction of DRV800 will lead to net cumulative savings of R$288,426,094 by decreasing the number of patients in 3^rd-line (43,052 vs. 31,526) and increasing on 2^nd-line(319,313 vs. 330,839). The budgetary impact of DRV800 is expected to account for an 8% increase(R$852,335.73 vs. R$922,544.97) of the total ARV budget for 2^nd-line and a 27%($733,391.23 vs. $537,041.571)reduction of the costs for the treatment of patients on 3^rd-line regime. CONCLUSIONS: the introduction of DRV 800mg in the Brazilian HIV ARV National Program is expected to led to a significant reduction of ARV(antiretroviral-drugs) expenditures in the next 5 years.