Opioids are known to cause dysfunction of the sphincter of Oddi. However, there are no reports on acute cholangitis due to opioid-induced dysfunction of the sphincter of Oddi. A 75-year-old woman with breast cancer, who had been prescribed oxycodone for lower abdominal pain due to unknown causes for 8 years, suddenly developed hypochondriac pain. We diagnosed the patient as having acute cholangitis and performed endoscopic retrograde pancreatography and technetium hepatobiliary iminodiacetic acid scan. The cause of acute cholangitis was considered to be opioid-induced dysfunction of the sphincter of Oddi. Six and nine days after admission, endoscopic sphincterotomy was performed, after which her upper abdominal pain resolved. Opioids increase biliary pressure and delay bile flow into the duodenum in patients after cholecystectomy. However, the actual clinical outcomes of using opioids for acute cholangitis and pancreatitis remain unknown. Thus, although opioid-induced dysfunction of the sphincter of Oddi is uncommon, it should be assessed in patients who are prescribed opioids.