From 1974-88 73 patients were treated for necrotizing enterocolitis (NEC) in the surgical department at the Children's Hospital of Cologne. 70% of these had other complaints and 77% were premature babies, of which 30% were small-for-dates. A greater than expected proportion of deaths occurred in babies not of low birth-weight: Of those above 2500 g 35% died and of those under 1500 g 20%. Initial signs and symptoms became apparent in 80% within the first two weeks. The most frequent signs were distended abdomen (81%), diffuse tenderness (46%), bloody stools (39%) and absent peristalsis (39%). Radiology showed edema of the bowel wall in 49%, free air in the abdomen in 38% and intestinal pneumatosis in 34%. It remains questionable whether peritoneal lavage could lead to earlier diagnosis and referral of the sick children to the hospital. The course of the disease was less severe when babies had received breast milk. Colon and distal ileum were involved most frequently. Laparotomy showed perforations of the bowel in 39 patients (64%), inflammatory alterations in 18 and necroses in 12. The survival rates improved within the period of 1974-88 from 64 to 79%. Thirty-two of the 51 survivors were available for follow-up: 9 patients (28%) had more than 4 stools/day, 8 (25%) were underweight, 8 (25%) suffered from food intolerance, 5 (16%) from diarrhoea, 4 (13%) from limited exercise tolerance. Physical retardation could only be seen in 3 children under the age of 2.