Obstructive sleep apnea (OSA) is highly prevalent in morbidly obese patients, although it is surprisingly underdiagnosed and undertreated. OSA can increase the risk of serious and life-threating complications in the perioperative period of bariatric surgery. Nevertheless, this potential risk can be minimized with adequate preoperative screening and perioperative management. The perioperative management of patients with OSA will affect the preparation for surgery, airway management, anesthetic selection, and monitoring. This chapter discusses and presents the best evidences available for the management of patients with OSA in order to decrease both the prevalence of undiagnosed patients and the morbidity associated with bariatric surgery.