Histocompatibility testing for liver transplantation remain some what enigmatic. Many investigators have noted that HLA compatibility doesn’t seem to benefit the overall group of liver transplant recipients. In fact, several studies has shown lower survival of HLA-DR -matched livers. HLA matching seems to have dual effect in liver transplant out-come: it reduces graft rejection but promotes other immune mechanism of graft injury related to viral infection (eg, cytomegalovirus and hepatitis virus) and recurrent disease. Moreover, a liver allograft has the distingushing feature of promoting a microchemerism associated with transplant tolerance, but liver graft-derived immunocompetent cells may also induce graft-vs-host-disease. Donor-specific-cross-matching has limited relevance to liver transplantation, because the liver allograft is relatively resistant to humoral rejection. In some sensitized patients a liver allograft may even protect a subsequent kidney transplant from hyperacute rejection.