Aim. To determine the risk of sarcopenia development and progression in bariatric patients after laparoscopic longitudinal gastric resection and after laparoscopic gastric bypass surgery.Methods. A comprehensive analysis was conducted, incorporating modern scientific literature and clinical guidelines to identify challenges in the diagnosis, treatment selection, and postoperative management of such patients. The study involved 30 patients, each of whom underwent a standardized preoperative outpatient assessment. This assessment included anthropometric measurements, as well as general and biochemical blood tests (such as blood glucose, total protein, albumin, and a lipid profile). To assess the degree of sarcopenia, a method involving computed tomography (CT) scanning of the head and neck was selected.Results. The BMI of the two groups being compared showed no statistical differences, with averages of 37.2 kg/m² and 40.6 kg/m², respectively. At follow-ups conducted 3, 6, and 12 months after surgery, both groups exhibited satisfactory weight loss results. Among the 15 patients who underwent laparoscopic sleeve gastrectomy, sarcopenia was detected preoperatively in 6 patients (40 %), while the remaining 9 patients (60 %) showed no signs of sarcopenia. However, 12 months post-surgery, signs of sarcopenia were observed in 8 out of 15 patients (53.4 %).Conclusion. Bariatric surgery induces significant changes in body composition, affecting not only fat mass reduction but also leading to a decrease in skeletal muscle mass. The progression of sarcopenia was more pronounced in patients who underwent laparoscopic gastric bypass surgery compared to those who had laparoscopic sleeve gastrectomy. Therefore, patients undergoing bariatric surgery may be at increased risk of developing or exacerbating sarcopenia.