Routinely collected data are valuable in obtaining information on complication types associated with elective surgery. International Classification of Diseases codes and surgical procedure "blocks" allow very sophisticated investigation of types of complications and differences in complication rates for different surgical approaches. The usefulness of such data relies on good documentation in the medical record, thorough coding and periodic data audit. The limitations of the method described here include the lack of follow-up after discharge, variable coding standards between institutions and over time (potentially distorting information on rates), lack of information on the causative factors for some adverse events, and a limited capacity to support investigation of particular cases. Hospitals should consider monitoring complication rates for individual elective procedures or blocks of similar procedures, and comparing adverse event rates over time and with peer hospitals as an integral part of their patient safety programs.