Healthcare safety and quality surveillance is increasingly conducted by public health agencies. We describe a biomedical informatics method that uses multiple public health data sources to perform surveillance of methadone-related adverse drug events. Data from Utah medical examiner records, vital statistics, emergency department encounter administrative data and a database of controlled substances prescriptions are used to examine trends in state-wide adverse events related to methadone. From 1997 to 2004, population-adjusted methadone prescriptions increased 727%, with evidence to suggest the rise in the methadone prescription rate is for treatment of pain, not addiction therapy. During the same period of time, population adjusted, accidental methadone-related deaths in medical examiner data increased 1770%. Population adjusted methadone-related emergency department encounters rose 612% from 1997 to 2003. Our results suggest that the increase in methadone prescription rates from 1997 to 2004 was accompanied by a concurrent increase in methadone-related morbidity and mortality. Although patient data is not linked between data sources, our results demonstrate that utilizing multiple public health data sources captures more cases and provides more clinical detail than individual data sources alone. Our approach is a successful biomedical informatics approach for surveillance of adverse events and utilizes widely available public health data sources, as well as an emerging source of public health data, controlled substance prescription registries.