Studies of human growth plate differentiation and function using isolated cells is not practical due to the difficulties of obtaining human growth plate tissue for analysis. Such problems would be alleviated, however, if it were possible to produce cell lines derived from human growth plate which maintain the appropriate chondrocyte phenotype. Here we report the establishment of a human foetal cell line, by retroviral transduction, with a hypertrophic chondrocyte-like phenotype.A mixed population of cells derived from a human foetal femur tissue of 6-9 weeks of gestation was retrovirally transduced with a vector comprising a temperature sensitive mutant of the simian virus 40 derived large tumour antigen, SV40tsA58, linked to a geneticin (G418) resistance marker. A cell line, HFFCL14, was cloned by limiting dilution. The quantitation of alkaline phosphatase (AP) activity showed that there was a two fold increase in basal level of AP activity in HFFCL14 when cultured at 39°C compared to 33°C, which corresponds to the oncogene's non-permissive and permissive temperatures, respectively. The addition of dexamethasone (Dex) and 1,25-(OH) 2 D 3 resulted in a dose dependent increase in AP activity in HFFCL14 cultured at 39°C, but not at 33°C. The extracellular matrix of HFFCL14, cultured at 39°C in mineralization medium (50ug/ml of ascorbic acid and 10mM β-glyceral phosphate) in the presence of 5 10 - 7 M Dex and 10 - 7 M Dex, was shown by Von Kossa stain method to be mineralized. PCR results of HFFCL14 cultured at 39°C demonstrated the expression of type X collagen but not type I collagen.The data so far provides evidence for HFFCL14 being derived from a hypertrophic chondrocytic lineage which can be induced to differenciate by Dex or 1,25-(OH) 2 D 3 . HFFCL14, therefore, furnishes us with unique cellular model with which to further elucidate the molecular and cellular mechanisms of human hypertrophic chondrocyte differentiation and biosynthetic function.