Method: Twenty-eight women, non-smokers, with no lung disease and BMI of 35-49,99 kg/m2, undergoing bariatric surgery by laparoscopy, were studied. Before surgery the patients were divided in two groups: Spirometer Group (SG) (n=13) and EPAP Group (EG) (n=15). Pulmonary function was evaluated by spirometry, thoracoabdominal (cirtometry) and diaphragmatic motion, on the preoperative and on the second postoperative day. Physiotherapy started on the day of surgery, each modality (incentive spirometry or EPAP) performed lasting 15 minutes. The deambulation and active exercises of upper and lower limbs were standardized for groups.