Medication errors are a major cause of morbidity and mortality among hospitalized children. Due to the small volumes of stock solution involved, even a large error may look as an unsuspiciously small dose. Strategies were implemented to reduce medication errors in a large tertiary pediatric hospital in Toronto. Starting in 1993, several initiatives were taken, including a new hospital computer system for medication ordering, a review process to remove hazardous drugs from wards where they are not needed immediately, and in the training of pediatric residents. The rates of reported medication errors were compared before and after these initiatives were taken. Compared to baseline, there was a steady and a statistically significant decrease in medication errors through the decade. Total errors (actual and potential) decreased for nurses and physicians by half and for pharmacists by 75%. Actual incidents decreased by half. Moderate and severe errors decreased by more than 70%. It was concluded that a combination of several initiatives to decrease system and human errors has resulted in more than a 50% reduction of medication errors reaching the pediatric patient.