Although we spend approximately one third of our lives sleeping, rarely do we consider that sleep may contribute to medical conditions. For gastroesophageal reflux, sleep or physiologic changes associated with the sleep state often promote or increase the likelihood of reflux and aspiration. These changes include the assumption of the supine position, a decrease in the arousal threshold, mechanical effects of the abdomen, and disorders associated with sleep. Of the sleep disorders, obstructive sleep apnea is associated with a high frequency of gastroesophageal reflux, probably due to the generation of negative intrathoracic pressures and obesity associated with the disease. Obstructive sleep apnea in patients with gastroesophageal reflux can lead to difficult-to-treat or refractory gastroesophageal reflux, predominantly nocturnal or early-morning symptoms, and unusual or uncommon manifestations that do not appear to reflect the underlying pathologic process. Under most circumstances, aggressive treatment regimens must be instituted for both disorders in order to effectively control symptoms. This article reviews the major information that is currently available on the relationship between obstructive sleep apnea and gastroesophageal reflux.