In children with symptoms secondary to malrotation of the intestine, a retrospective statistical study was undertaken to identify factors associated with an increased risk of mortality. Between 1964 and 1989, laparatomy was performed on 182 children. For study purposes, the children were divided into three groups. Group I included 71 patients with an obstruction only in the duodenum. The remaining 111 children, all of whom had midgut volvulus, were further divided; those without gut necrosis (79) into group II, and those with necrosis (32) into group III. One child each died in groups I and II, and 15 in group III. In all children we evaluated the relationship between mortality and age at presentation, presence of associated serious abnormalities, time from onset of symptoms to surgery, and the presence of necrotic bowel. For group III, we considered the influence of percentage of bowel resected on mortality. In these 182 children the factors associated with an increased risk of mortality were presence of necrosis (P