The Prescription Drug Use Questionnaire (PDUQ) is one of several published tools developed to help clinicians better identify the presence of opioid abuse or dependence in patients with chronic pain. This paper introduces a patient version of the PDUQ (PDUQp), a 31-item questionnaire derived from the items of the original tool designed for self-administration, and describes evidence for its validity and reliability in a sample of patients with chronic nonmalignant pain and on opioid therapy. Further, this study examines instances of discontinuation from opioid medication treatment related to violation of the medication agreement in this population, and the relationship of these with problematic opioid misuse behaviors, PDUQ and PDUQp scores. A sample of 135 consecutive patients with chronic nonmalignant pain was recruited from a multidisciplinary Veterans Affairs chronic pain clinic, and prospectively followed over one year of opioid therapy. Using the PDUQ as a criterion measure, moderate to good concurrent and predictive validity data for the PDUQp are presented, as well as item-by-item comparison of the two formats. Reliability data indicate moderate test stability over time. Of those patients whose opioid treatment was discontinued due to medication agreement violation-related discontinuation (MAVRD) (n=38 or 28% of sample), 40% of these (n=11) were due to specific problematic opioid misuse behaviors. Based upon specificity and sensitivity analyses, a suggested cutoff PDUQp score for predicting MAVRD is provided. This study supports the PDUQp as a useful tool for assessing and predicting problematic opioid medication use in a chronic pain patient sample.