he orthotopic transplantion of human hepatocellular carcinoma wascarried out effectively and safely by adnministering with thiopentalsodium (30mg/kg) dissolved in 30% alcohol for anaesthesia and withspongia gelatinosa absorbentia soaked in Reptilase (250 ki U/ml) forcoaguiation in nude mice. Two human hepatocellular carcinoma celllines (HHC4 and HHC15) set up in nude mice were orthotopic-ally transp lanted into liver of nude mice successfully underSPF conditions. Orthotopic xenograftes grew well and propagatedsteadily and secreted AFP consistently in correspondence with theincreased volume of tumor. The rate of orthotopic propagation inHHC4 was increased (P<0.01) by administration of CCl4 ( 0.5% )0.1ml dissolved in olive oil before a week of xenograft. Withoutany treatment, HHC15 orthotopic transplantation had higher rate ofinoculation ( 100%) than that of HHC15 subcutaneous transplantation(93.3%), Based on the hepatocellular necrosis damaged by CCl4,the orthosopic model of hepatocellular carcinoma in nude mice wassimilar to the pathophysiological characteristics of pathogenesis ofthe hunfian hepatocellular carcinoma. These models will contribute tothe screening antitumor drugs.