Background: Endoscopic methods, especially the intragastric balloon (IGB), have been shown to be effective for the treatment of excess weight. This study aimed to assess the tolerance, complications and efficacy of excess weight treatment with a nonadjustable IGB during 6 months. Methods: A total of 5,874 patients treated with a liquid filled IGB (600-700mL) and followed up by a multidisciplinary team were evaluated. Participants presented an initial body mass index (BMI) [?]25 kg/m 2 and were stratified according to sex and degree of overweight (pre-obesity and obesity grade I, II and III). Results: The incidence of complications was 7.32% (n=430): 6.10% (n=357) early IGB removal, 0.20% (n=12) gas production inside the balloon, 0.54% (n=32) leakage, 0.32% (n=19) pregnancy, 0.07% (n=4) gastric perforation, 0.05% (n=3) upper digestive bleeding, 0.01% (n=1) Wernick Korsakoff syndrome due to excessive vomiting, 0.02% each (n=1) pancreatitis and esophagus perforation. The 5,444 remaining patients (4081 women, 38±38years) presented a weight loss of 19.13±8.86kg and a BMI decreased significantly (p<0.0001) (36.94±5.67 vs. 30.08±5.06 kg/m 2 ). The % total weight loss (%TWL) was 18.42±7.25% and % excess weight loss (%EWL) 65.66±36.24%. The treatment success rate (%TWL[?]10%) was 85%. The %EWL was higher in the pre-obese group (122.19%), followed by obesity grades I (76.67%), II (56.01%) and III (45.45%), with p<0.0001 for each group. %EWL was higher in women (69.71%) than in men (53.39), with p<0.0001 for each group. There was also a statistical difference between the TWL and EWL groups, with p<0.001 for all analyzes. Conclusion: Endoscopic IGB treatment for excess weight is an excellent therapeutic option for patients with different degrees of overweight.