The aim of a study: The aim of the study was to assess the efficiency of patients with pathological obesity after laparoscopy sleeve gastrectomy in a six-minute march test. Material and methods: The study was conducted on a group of 30 patients with giant obesity hospitalized in the Surgery Clinic of the 10th Military Research Hospital and Polyclinic in Bydgoszcz. The patient was evaluated on the day before the laparoscopic gastrectomy and one month after the surgery. In all patients a six-minute march test was performed and the author's questionnaire was used. Results: As a result of the operation, an average weight loss of 10 kg was observed in the patients, an improvement in efficiency, as well as the resignation or significant reduction in symptoms of coexisting diseases. Based on a 6-minute march test it was found that the distance covered by the patients increased by 30 m. Conclusions: 1. Bariatric surgeries are an effective method of weight reduction for patients with massive obesity. 2. As a result of the procedure, the number of ailments complained about by the patients has decreased. 3. The weight reduction in obese people as a result of a bariatric procedure, increases the functional ability to walk, assessed with a 6-minute march test. 4. The 6-minute march test provides useful information on the functional status of obese patients undergoing bariatric surgery. It is a simple, safe and efficient method for assessing the performance of patients with severe obesity.