A total number of 1628 cases with Hirschsprung's disease were collected in a nationwide survey; 181 of the cases had additional anomalies. The overall incidence of additional anomalies was 11.1% (181/1628). Down's syndrome and cardiac anomalies occurred in 2.9% and 2.5%, respectively: A greater incidence than seen in the general population. The longer the aganglionic segment, the higher the incidence of additional anomalies. Megacystis and megaureter were less common. Intestinal atresia and stenosis were seen in 15 patients, the rate being 0.9%. The overall mortality in patients with additional anomalies was higher at 17.7% (32/181) than in those without.