Obstructive sleep apnea (OSA) and extraesophageal reflux (EER) are common chronic diseases and share several similar risk factors. The prevalence of gastroesophogeal (GERD) in OSA patients is significantly higher than the general population; however, no temporal or causal relationship has ever been demonstrated between the two. The purpose of this review is to understand the association between obstructive sleep apnea (OSA) and extraesophageal reflux disease (EER) in the adult population. We conclude that CPAP treatment of OSA significantly reduces GERD symptoms and acidic pH exposure in the esophagus and this improvement with CPAP physiologically occurs in the presence or absence of OSA; and treatment of GERD in OSA patients improves the number of arousals during sleep, but only one study showed a significant difference in apnea.