Missed appointments affect patients' health in addition to reducing practice efficiency. This study explored the rate and reasons of non-attendance among patients with chronic illnesses. It was a cross-sectional descriptive study carried out in a family practice clinic over a one-month period in 2004. Those who failed turn up for scheduled appointments were interviewed by telephone based on a structured questionnaire. Out of 671 patients, the non-attendance rate was 16.7%. Sixty-seven percent of non-attenders were successfully interviewed. Males (p = 0.01), Indians (p = 0.015), patients with coronary artery disease (p = 0.017), multiple diseases (> 4) (p = 0.036) and shorter appointment intervals (p = 0.001) were more likely to default. The main reasons for non-attendance were: forgot the appointment dates (32.9%), not feeling well (12.3%), administrative errors (19.1%) and work or family commitments (8.2%). The majority would prefer a reminder through telephone (71.4%), followed by letters (41.3%). In conclusion, appropriate intervention could be taken based on the reasons identified in this study.