In order to identify possible underlying ganglion-cell disorders, specimens have been taken in neonates and infants with intestinal obstruction treated between January 1988 and June 1992. NID was confirmed in 3 patients with intestinal malformation, 2 patients with neonatal intestinal obstruction, 3 patients with meconium peritonitis, 1 patient with persistent constipation after Duhamel's pull-through for Hirschsprung's disease and 1 patient with rectal stricture after conservative treatment for necrotising enterocolitis. Additionally, NID was found in 1 patient with recurrent prolapse of an ileostomy. Associated Hirschsprung's disease has been ruled out by additional rectal suction biopsies in patients where specimens have been collected at laparotomy first. Development of NID in previous normal bowel, the association of NID with intestinal malformations as well as the clinical heterogeneity of patients with NID of the present series suggest that NID is a reaction of the neural intestinal system caused by congenital obstructive factors or inflammatory diseases.