Molecular Adsorbent Recirculating System (MARS) is a blood-filtering system designed to provide biological artificial liver support. We describe its use in a small child to illustrate its effectiveness and practicality in this age group. A 15-month-old male underwent split liver transplantation for acute liver failure following bone marrow transplantation. After development of graft dysfunction we instituted MARS-dialysis. MARS therapy led to a dramatic fall in serum bilirubin and transaminases. Liver synthetic function was not affected. This was accompanied by a stabilization of the patients clinical condition until repeat split liver transplantation was performed 2 weeks after the first graft. MARS-dialysis is practical in the small child. In this case, it did not provide definitive treatment but was an excellent bridging therapy before retransplantation.