We report on the emergency separation of xyphophagus-omphalophagus conjoined twins. The twins were delivered by Caesarean section in the 35th week of pregnancy. They were conjoined between the omphalus and xyphoid process and had a fusioned common liver. All other organs including the peritoneal cavities were separate. One of the twins showed normal development, whereas the other was multifocally deformed with microcephalus, complex vitium cordis, microintestine and malformation of the extremities. Due to the extremely poor general condition of the deformed twin immediate emergency separation was mandatory even before completing the diagnosis of circulatory condition and liver formation. The deformed twin died during the operation and the fully developed twin on the 7th day after the operation after cerebral haemorrhage with haemorrhagic diathesis. The report gives a detailed description of the specific foetal circulatory condition and the problem of a postoperatively occurring partial necrosis of the liver.