AbstractThe feasibility of using a segmental auxiliary liver graft comprising some 40 per cent of the total liver mass fed by the renal vein rather than the portal vein is studied. An autotransplantation technique is described which has the advantage of excluding the problems associated with rejection. Two groups of dogs are investigated in one of which an orthotopically placed segment of liver is also retained. Data are presented which show that a heterotopically placed segment comprising only 40 per cent of the total liver mass can be transplanted heterotopically and in the absence of portal vein influence can maintain animals in good health for months. Furthermore, the presence of an orthotopically situated segment with a normal haemodynamic supply does not inhibit the function of a heterotopic one. The results suggest that in the absence or inhibition of the rejection mechanism heterotopically placed partial liver grafts can function well and be life‐supportin