Endoscopic intragastric balloon (IGB) placement is a minimally invasive treatment for morbid obesity that is sometimes used as a preparatory step before surgical intervention. This study was performed to analyze the changes in the stomach wall induced by IGB placement, with particular emphasis on pathomorphology, inflammatory markers, and tissue growth factors.In total, 30 patients with morbid obesity were prospectively analyzed. A total of 16 patients with body mass index (BMI) ≥ 53 kg/mThe IGB group had a longer median hospital stay than that of the non-IGB group. Compared with the non-IGB group, the IGB group had a thicker stomach wall, more submucosal fibrosis, and increased amounts of growth factors and inflammatory markers.Patients with IGB placement before LSG showed greater changes in the stomach wall than those of patients who received LSG alone. IGB placement was associated with stomach muscle layer thickening, submucosal fibrosis, and increased levels of inflammatory markers and tissue growth factors.