OEIS complex refers to a combination of defects consisting of omphalocoele, exstrophy of the cloaca, imperforate anus, and spinal defects. The incidence of the OEIS complex is very rare, estimated to occur in 1 of 200,000-400,000 pregnancies. The aetiology of the OEIS complex is still unclear, single defects in blastogenesis and mutations in homeobox genes, such as HLXB9, have been suggested to be responsible for the development of the OEIS complex. Moreover, higher incidence of OEIS in monozygotictwins suggests a possible genetic contribution to the occurrence of this multisystem defect. We here report the peculiar case of OEIS complex in a dizygotic twin pregnancy. Prenatal diagnosis of OEIS by ultrasound examination is possible but difficult. Sonographic detection of an omphalocoele in the presence of an open neural tube defect should prompt a search of OEIS-associated defects. Accurate prenatal diagnosis by ultrasound and/or diagnosis of the OEIS complex at autopsy are important for detailed counselling of the parents and perinatal management.