Ileus during pregnancy is a rare complication. Malrotation in the adult is an even rarer finding. A case of a woman who developed an ileus in her seventeenth week of pregnancy is presented. At surgery the cause appeared to be a malrotation of the midgut. The incidence and causes of ileus during pregnancy are discussed. Also a short description of the different forms of malrotation are presented. New insights in the etiology of malrotation based on experiments with rats are mentioned.