OBJECTIVES In the latest years several drugs demonstrated to increase survival in mCRPC patients post chemotherapy failure. However, issues remain related to the treatment sequencing of these drugs. The aim of this study is to estimate the budget impact of the introduction of enzalutamide in the Brazilian Private Health System. METHODS A deterministic state transition budget impact model (BIM) was developed to estimate treatment costs of mCRPC patients after chemotherapy failure over a 3-year time horizon. Budget impact was estimated comparing a baseline scenario including mandatory coverage drugs (abiraterone, cabazitaxel) with an alternative scenario including all treatment options (abiraterone, cabazitaxel and enzalutamide). Target population, dosing, duration of therapy and sequencing was based on scientific literature. Pharmaceutical direct costs were based on factory price, assuming parity price of enzalutamide and abiraterone. Univariate Deterministic sensitivity analysis was conducted to determine the impact of parameters on results. RESULTS The BIM estimates that a total of 5,789 patients will be treated in the next three years, with annual cost estimates in the baseline scenario of R$83,944,041 in year 1, reaching R$198,507,065 in year 3 of the simulation. The introduction of enzalutamide would incur a total increase in costs of R$16,649,325 after 3 years. In deterministic sensitivity analysis, enzalutamide price, proportion of patients receiving additional treatment line and duration of therapy were the most important variables that impacted results, with the alternative scenario remaining more costly than the baseline scenario in all simulations, incurring additional costs ranging from R$6,634,955 to R$38,818,233. CONCLUSIONS Considering current available evidence regarding treatment sequencing, the introduction of enzalutamide is expected to increase costs to the Brazilian Private Health System.