Obstructive sleep apnea-hypopnea syndrome (OSAHS) is characterized by successive episodes of cessation or decrease in respiratory airflow, in which obesity is an important risk factor. The prevalence of the disease in morbidly obese patients is approximately 70%. Treatment is based on the use of continuous positive airway pressure (CPAP) and weight loss in obese patients. Weight loss by dieting often produces unsatisfactory results, and the use of CPAP does not show good adherence because of being long-term and uncomfortable. Bariatric surgery has emerged as the treatment for morbid obesity and various associated co-morbidities. This article reviews the principal studies that evaluate the modifications in obstructive sleep apnea after bariatric surgery, showing that surgery is an effective treatment for the management of OSAHS in morbidly obese patients.