We report drug errors during anesthesia. The data were retrieved from the incident reports in a period of June 2000 to June 2003 at the Department of Anesthesiology, Fukuoka University Hospital. Drug errors occurred in 18 (0.12%) of 15,271 patients who were managed by anesthesiologists during the period. Among the 18 events, most frequent errors were 12 events of administration of wrong drugs. Errors in dosage were five, and wrong route of administration in one. There were no serious sequelae in the 18 patients.