BACKGROUND: Unexpected cancellation of the elective operation on scheduled day is stressful event to both of patients and doctors, especially when there is little explanation and understanding. Above all, it is against cost-saving policies in hospital management. Thus the author investigated the rate, distribution and causes of cancelled cases to get help to make plans to reduce the cancellation rates. METHODS: From March 1st in 1996 to February 28th in 1997, all operation schedules were reviewed and cancelled cases on scheduled day were analyzed. All the elective operations except emergency operations under general, regional or local anesthesia were included in this analysis. Total cancellation rate was analyzed according to surgical departments, month, week day, age and causes. In statistical analysis, SAS program was used. RESULTS: Total number of cancellation was 424 cases and mean cancellation rate was 8.47%. In analysis of cancellation rate by months, it was highest in October and lowest in November. In August, October and December the cancellation rates were higher than the other months. It was higher on Tuesday and Thursday. Most common causes of cancellation was the problems related patient's condition, especially related to coexisting diseases. Among these, cardiac disease was predominant. Non-medical causes were predominant than medical causes in most cancelled cases. CONCLUSION: Trying to reduce the cancellation rates is suggested as one of methods that will make the quality and quantity of medical services better. Careful preoperative evaluation of patient and consultation of abnormal findings or laboratory data before hospitalization, appropriate scheduling of operation, complete preparation of operation apparatus, through all these, firm establishment of doctor-patient rapport are core element of reducing of cancellation rate. So, attention and support by not only anesthesiologist but surgeons and hospital managers are needed to achieve these goals of reducing of cancellation rate.