Rat hepatocytes were isolated by collagenase perfusion method and cultured on the collagen coated dish or on the floating collagen membrane. Using the primary cu1tured hepatocytes, the efficiency of cell attachment and the hepatic functions such as gluconeogenesis, ureogenesis and albumin synthesis were studied. The cell viability was kept above 50% until 5 days and the hepatic functions of ammonia metabolism and albumin synthesis were maintained until 7 days. Floating collagen membrane was found to be more efficient than the collagen coated dish for the maintenance of hepatic function in-vitro.