Bone morphogenetic protein (BMP) has the ability to induce ectopic bone, while the action of transforming growth factor β (TGF β) is to stimulate proliferation of osteoblasts and chondrocytes as well as the production of extracellular matrix. The aim of the present study was to study their synergistic actions in bone formation. Three kinds of complexes, recombinant human BMP2 (rhBMP2), TGF β and rhBMP2/TGF β in ceramic bovine bone (CBB), were made and then implanted into the thigh muscle pouches of mice. The histological reactions of the implanted areas were studied at intervals of 3, 5, 7, 14 and 21 days. The results showed that, except for the implants with TGF β alone, both rhBMP2 and rhBMP2/TGF β implants exhibited new ectopic bone formation. The morphometric study revealed that the quantity of newly formed bone induced by rhBMP2/TGF β was obviously greater than by rhBMP2 alone. These results indicate that TGF β in combination with BMP may enhance formation of ectopic bone.