The characteristics of patients currently abusing controlled-release (CR) oxycodone admitted for inpatient detoxification were ascertained from medical record review of 48 inpatients with CR oxycodone dependence. Patients were categorized according to the manner in which they initially received the drug: illicitly or by prescription for legitimate medical use. Fifteen of the 48 patients (31%) initially obtained a CR oxycodone prescription legitimately for a medical condition. While none of these 15 patients had a history of prior opioid misuse, they were more likely than illicit CR oxycodone users to report prior detoxifications (P<0.03) as well as a lower mean age of first alcohol use (legitimate=11.7 versus illicit=14.7, P<0.05) and first illicit drug use (legitimate=12.8 versus illicit=15.8, P<0.05). These findings suggest that a history of substance abuse is common among patients abusing CR oxycodone, including individuals for whom CR oxycodone was initially legitimately prescribed for pain.