OBJECTIVE: This study measures the effectiveness of post card appointment reminders in a residency-based family practice center. METHODS: Outcomes of 1,380 consecutive appointments before institution of reminders were compared with 1,303 appointments afterward. Then, 140 patients were informally surveyed in follow-up. RESULTS: Before reminders, overall office no-show rate was 13.0%, cancellations were 19.4%, and arrivals were 67.6%. No-shows correlated with length of time from scheduling date to appointment date, seeing a resident rather than faculty, and patient payment classification (p < 0.0001). Post card reminders did not significantly improve arrivals by patients or change no-shows to cancellations. The reminders were well received by patients. CONCLUSIONS: Post card appointment reminders were simple to institute and appreciated by patients but had little effect on improving appointment-keeping behavior.