This study examined claims data from 2011 to 2015 to assess the impact of Prescription Drug Monitoring Program (PDMP) policies on opioid-related Emergency Department (ED) visits or inpatient admissions among patients prescribed opioids. Comprehensive use mandates were associated with a significant reduction in the probability of ED visits or inpatient admissions; the impact was greater among older patients. Delegate laws and interstate data sharing were associated with nonsignificant reductions in ED visits or inpatient admissions.