We examine ambulance runs for suspected opiate overdose from 1997 to 2002 using a Rhode Island Department of Health database. Of the 8,763 ambulance runs for overdoses, 18.6% were for suspected opiate overdoses. Most cases were males under age 54. Suspected opiate overdoses were more likely to occur in a private residence, were more frequent on Fridays and Saturdays, and peaked in incidence around 9:00 p.m. The incidence rate of suspected opiate overdose by year was similar. The study results may help identify areas for preventive intervention and demonstrate the limitation of using naloxone as a marker of opiate overdose events.