Hepatobiliary sequential scintigraphies by 99m Tc-ROTOP-EHIDA were carried out for judging the dual liver system after experimental auxiliary transplantation of a part of the liver. A functional advantage of the host liver in contrast to the transplant was found in all cases investigated. Ischemic transplant damages could be detected in all experiments and were scintigraphically recognised at an early stage. In addition to transplants with a functioning entire parenchyma, the investigations showed transplants with functionally active parenchyma zones and such ones without any functional evidence. A quantifiable determination of the global functional capacity of the hepatobiliary system of both livers was possible and also the evidence on residual functions. The different behaviour of the kinetics of the radio-pharmacon with normal function and in case of hepatic ischemia is discussed.