Abstract： AIM: To study a possible synergism between recombinant human bone morphogenetic protein protein-2(rhBMP-2) and transforming growth factor-β(TGF-β) in osteoinduction and osteogenesis. METHODS: 210 BALB/c mice were divided into three groups at random, 70 in each group, and composites were implanted in the right thigh pouchs. Mice receiving composite of rhBMP-2/ carrier and carrier only served as the controls. In order to investigate the process of osteogenesis, histological analysis was performed 12 hours, 1, 2, 3, 5, 7, 9, 11, 14, 17 and 21 days after the implantation; meanwhile, alkaline phosphatase activity and calcium content were measured 7, 14 and 21 days after the implantation. RESULTS: Proliferation and differentiation of mesenchymal cells, chondrogenesis and osteogenesis induced by the composite of rhBMP-2/TGF-β/carrier appeared earlier than those induced by the composite of rhBMP-2/carrier. The amount of osteogenesis was greater than that in the group of rhBMP-2/carrier. Peak of ALP activity in the experimental group occurred earlier than those in the controls and calcium content was higher than those in the controls obviously. However, only a few proliferating mesenchymal cells were observed in the carrier group 21 days after the implantation. CONCLUSION: rhBMP-2 and TGF-β exert a synergetic action in regulating osteoinduction and osteogenesis.