Over a 4 year period, nine of 180 (5%) infants weighing less than 2000 G, admitted to the Aga Khan University Hospital (AKUH) developed necrotizing enterocolitis (NEC). An outbreak of NEC occurred in 1989, during which six infants developed the clinical illness. Overall incidence was 1.1%. Thirty-one birth weight and gestation matched controls were selected for comparison. Risk factors usually considered as predisposing factors, i.e., low 5 min Apgar score, rate of maternal complications, respiratory distress syndrome, mechanical ventilation, umbilical catheterisation, patient ductus arteriosus, use of antibiotics and feeding practices were found with equal frequency in both cases and controls. Six infants had positive blood and/or peritoneal fluid cultures (66%) compared to only five (16%) in the control group (P less than 0.01). Our data suggests that prematurity and sepsis are important predisposing factors for development of NEC.