Vanadium is an essential trace element but has not been identified with a specific biogical role. To study the direct effects of vanadium on osteoblast, we incubated murin osteoblast-like (MC3T3-E1) cells with various concentration of vanadium oxide & sodium orthovanadate. This study was designed to investigate the effect of vanadium on DNA synthesis, alkaline phosphatase (ALP) activity, cAMP formation responsive to parathormone(PTH) and type I α 2 collagen ribonucleic acid (mRNA) level in murin osteoblast-like (MC3T3-E1) cells. The cells were cultured in a -minimal essential medium(α -MEM) supplemented with 10% fetal bovine serum (FBS) and then changed to 0.1% FBS with various concentration of vanadium oxide & sodium orthovanadate. Quiescent cultured MC3T3-E1 cells incubated for 24 hours with 2,5,10,15,20 µM vanadium oxide incorporated [³H]Thymidine; every concentration showed increases in [³H]Thymidine incorporations dose dependant manner, the greatest response occurred at 20µM. Quiescent cultured MC3T3- E1 cells incubated for 3days with 2,5,10,15,20 µM vanadium oxide, for 2 days with sodium orthovanadate and alkaline phosphatase was assayed with disodium phenyl phosphate as substrate. Vanadium oxide increased the alkaline phosphatase content in MC3T3- E1 cells at 2 µM & 6µM; the greatest response occurred at 2µM. But decreased at other content. sodium orthovanadate increased alkaline phosphatase content in MC3T3-E1 cells at all concentration ; the greatest response occurred at 4µM. Quiescent cultured MC3T3- E1 cells incubated for 3days with 5,10µM vanadium oxide, with 5,8µM sodium orthovanadate and cAMP formation was measured by Radioimmunoassay(RIA). Vanadium oxide & sodium orthovanadate showed the tendency of inhibitory effects on cAMP responsiveness to PTH in MC3T3-E1 cells. Quiescent cultured MC3T3-E1 cells incubated for 24hours with 10,20µM vanadium oxide, with 5,10µM sodium orthovanadate and Type I α2 collagen ribonucleic acid (mRNA) expression was studied by Northern blot analysis. Northern blot analysis of vanadium oxide treated cells showed decreasing effects 0& sodium orthovanadate revealed increasing effects in type I &2 collagen ribonucleic acid (mRNA) level.