Difficulty in obtaining human liver specimens has made a delay in the development of methodology for isolation and primary culture of human hepatocytes compared to animal hepatocyte cultures. Recently the collagenase-liver-perfusion technique, which was developed for rat hepatocyte isolation, has been applied to prepare isolated human hepatocytes. This method greatly improved the yield and viability of hepatocytes of human liver tissues. Since then, the isolated human hepatocytes and their primary culture have been widely used for studies of hepatic metabolism, regeneration, transplantation, hepatitis B virus infection, hepatotoxins, detection of human carcinogens, hepatocarcinogenesis and so forth. These current studies were reviewed.