This study compared mail, telephone, and control strategies to reduce the rate of broken appointments in a pediatric outpatient department. Based on 1,039 randomly assigned appointments, the mail strategy had a broken appointment rate of 29.1 per cent, the telephone strategy of 25.3 per cent, and the control of 44.2 per cent. Both strategies were significantly effective, but the difference between them was not significant. Patients without telephones had a higher rate of broken appointments than patients with telephones. Mailed reminders are the more cost-effective intervention.