We examined the causes of delaying or cancellation of the elective surgery at Seoul National University Children's Hospital. The total numbers of pediatric patient for the elective surgery during September 1, 1994, to November 30, 1994, were 1287 and that of delaying or cancellation of surgery were 135. The fraction of medical causes of delaying of the elective surgery was 62.2%, and that of non-medical causes of the elective surgery was 36.3%, and 1.5% was unknown. The single most frequent cause was upper respiratory infection, 42.2% of total delays, and the second was that patient had not be admitted as 16.3%o of total delays. The third frequent cause was no indication for surgery as 6.7%, the fourths were fever and inadequate preparation for surgery (5.2%), and the sixth was that the patient had refused to give an informed consent (3.7%), etc.