OBJECTIVES: To estimate the budget impact of adding omalizumab to standard therapy (ST) in patients with uncontrolled severe allergic asthma, from the perspective of the Brazilian private healthcare system, over a 5-year time horizon. METHODS:  A budget impact model was developed to calculate the budget impact for Brazil, based on local epidemiological and drug cost data. The eligible population was based on the following inputs: 2013 population estimate (age ≥6 years): 183 million; prevalence of asthma: 10%; proportion of patients diagnosed and receiving treatment: 6.5%; percentage with allergic asthma: 69%; percentage with immunoglobulin E (IgE) ≥30 IU/mL: 78.7%; percentage with uncontrolled, severe disease: 2.4%; proportion of population using the private healthcare system and medications: 25.1%. For the following years, an annual population growth rate of 1.17% was assumed. Average doses, resource utilization per exacerbation and proportion of patients who respond to omalizumab were obtained from the INNOVATE trial. Direct costs, including omalizumab purchase and the costs of healthcare consumption related to exacerbations and routine visits. These costs were calculated from the perspective of the private healthcare payer. Omalizumab uptake was assumed to be 17%, 35%, 55%, 75% and 95% of eligible population for years 1 to 5, respectively. RESULTS: The number of patients eligible for add-on omalizumab therapy that met the eligibility criteria was estimated to be around 3,887 in the first year. The annual budget impact of omalizumab was approximately BRL25 million, BRL50 million, BRL77 million, BRL104 million and BRL131 million for years 1 to 5, respectively (BRL1=USD0.492). CONCLUSIONS: The budget impact for the private healthcare system in Brazil of adding omalizumab to ST was approximately BRL131 million at the end of year-5. Considering that the total population using the private healthcare system in Brazil is around 45.4 million, this represents a relatively small impact on the payer’s budget, of BRL2.90 per beneficiary.