The Prescription Opioid Misuse Index (POMI) was developed and used in a larger study designed to assess correlates of OxyContin abuse in pain patients prescribed OxyContin, patients treated for OxyContin addiction, and individuals incarcerated for OxyContin-related charges. The POMI was administered to 40 subjects with addiction problems and 34 pain patients who had received OxyContin for pain. Receiver operating characteristic curve analysis indicated that endorsing two or more of six items reliably classified a person as at risk for misuse of their medication. When comparing drug abuse/dependence in subjects classified as misusers or users, significantly more misusers received a diagnosis for alcohol (p < .01), illicit drugs (p < .05), and other prescription medications (p < .05) and reported greater lifetime use of alcohol (p < .002) and illicit drugs (p < .01). No between-group differences were found regarding psychiatric problems. The POMI appears to be a sensitive and specific instrument for identifying patients who misuse opioid medications.