Previous studies have examined missed appointments in psychiatric outpatients, but military patients have not been studied. The objective of this study was to describe the characteristics of patients who miss or cancel appointments in a military outpatient psychiatry clinic. During a 75-day period, patients presenting to the Walter Reed Army Medical Center outpatient psychiatry clinic were tracked for missed and canceled appointments. Patients included active duty and retired service members as well as military dependents. For each missed or canceled appointment, the treating psychiatrist completed a questionnaire detailing clinical information and information regarding the missed or canceled appointment. Within the study period, 20% of all scheduled appointments were either missed or canceled. Fifty-two percent of the patients who missed or canceled appointments called within 2 weeks to reschedule. Of those patients who missed or canceled appointments, 27% missed or canceled more than once during the study period. Active duty patients were significantly more likely to miss and less likely to reschedule than military dependents and retirees.