There has been a growing recognition of chronic pain that may be experienced by patients. There has been a movement toward treating these patients aggressively with pharmacologic and nonpharmacologic modalities. Opioids have been a significant component of the treatment of acute pain, with their increasing use in cases of chronic pain, albeit with some controversy. In addition to analgesia, opioids have many accompanying adverse effects, particularly with regard to stability of breathing during sleep. This article reviews the existing literature on the effects of opioids on sleep, particularly sleep-disordered breathing.