OBJECTIVES:: Bariatric surgery has predictable outcomes. However, additional treatments might be necessary in some cases, such as the antibiotics treatments that could lead to higher costs and utilization resources, independent of the reimbursement model and length of stay.The aim of this study is to evaluate the feasibility to identify antibiotic patterns and its association with higher costs in a large health insurance claim database in patients submitted to bariatric surgery. METHODS:: A retrospective analysis of electronic claims from 1733 patients submitted to a laparoscopic bariatric surgery during the year of 2013. Prophylactic or therapeutic use was defined according to its start date and guidelines of use. Total hospital cost and resources use were registered. Association of antibiotic use and long length of stay was evaluated by Qui-square test. Total costs and length of stay were evaluated by Mann–Whitney test. The study investigated the private payer perspective. RESULTS:: The average age of studied population was 36.21 ± 9 years, with 75.3% of women. The total median length of stay was 2 (2-3). The prevalence of therapeutic antibiotic use was 5.48%. The average reimbursement for patients who received therapeutic antibiotic was R$ 36,497.41± 68,151and R$ 16,476.65±11,040.01 for prophylactic antibiotic only in the Fee for service contracts and R$ 32,730.71±39,331 for therapeutic antibiotic use and R$ 22,352.71±5,167 for prophylactic antibiotic only in the pre-approved fixed reimbursement model (p<0,001). The length of stay did not differ from both groups (prophylactic and therapeutic). There was an association between use of therapeutic antibiotic and long length of stay (≥5 days), p<0,001). CONCLUSIONS:: These real-world data suggested that antibiotic use is a feasible way to identify patients with higher costs and resources use, independent of the length of stay and type of reimbursement. Bariatric surgery patients receiving therapeutic antibiotics increase the total payer expenditure.