Poor appointment keeping is a major problem in many health facilities. At The Anthony L. Jordan Health Center, we studied 670 pediatric appointments to see if a postal card reminder mailed one week before the appointment would make a difference in the keep rate (kept plus canceled appointments, divided by kept plus canceled plus broken appointments). The appointments studied were 12 days to eight weeks from the time of scheduling. In the control group, the keep rate was 48%. Those receiving mailed reminders had a keep rate of 64%, a significant difference (X2 = 16.92; p < 0.001). The effects on the keep rate of age, interval to appointment, time of day, referral pattern, reason for appointment, and prior keep rate were minor. The use of a mailed reminder can improve appointment keeping and facilitate better care and more efficient scheduling and use of personnel.