Background: The aims of this study are to evaluate the efficacy and safety of intragastric balloon (IB) to reduce the weight and body mass index (BMI) in severely obese adolescent females and to describe the changes in the liver enzymes and lipid and glucose metabolism biomarkers. Methods: This study included 10 severely obese post-menarche adolescent females. We evaluated anthropometric data, lipid profile, glucose metabolism biomarkers, and liver enzymes before insertion and after removal of the IB. Results: BMI and weight reduction were larger during the first month of intervention. Especially in the first week, there was a reduction of 1.74 ± 0.46 kg/m 2 (p = 0.004) and 6.46 ± 1.52 kg (p = 0,002), respectively. After 3 months, there was an average BMI reduction of 4.29 ± 1.04 kg/m (p = 0.005) and weight reduction of 12.9 ± 3.08 kg (p = 0.004). From the initial moment to study conclusion, there was a statistically significant reduction in insulin levels (9.0 ± 2.8 U/mL; p = 0. 012) and in homeostatic model assessment-insulin resistance (2.0 ± 0.6; p = 0.009). Five patients reported, during the first week, epigastric pain; nausea and vomiting were observed in two patients. No adolescents presented dysphagia during IB use. Conclusion: IB use in adolescent females with severe obesity in association with a conservative multidisciplinary treatment had a positive impact in BMI reduction, with few adverse effects. There was also an improvement in insulin resistance.