INTRODUCTION: The hamstring tendon autograft is widely used for anterior cruciate ligament reconstruction because of its superior tensile strength and lower donor site morbidity. The successful reconstruction surgery depends on not only initial graft fixation but also biologic integration of the graft. The healing process of transplanted tendon graft to bone via the development of fibrovascular tissue has been revealed in both animals and humans. In recent study, it has been demonstrated that some growth factors may promote maturity of the fibrous interface or remodeling of the bone tunnel, but the mechanism remains unclear. To identify how the growth factors regurate the healing process between the tendon graft and bone, we assessed the expressions of basic fibroblast growth factor (bFGF), a potent mitogenic agent on a variety of cells of mesenchymal origin, and vascular endothelial growth factor (VEGF), an intensely angiogenic factor that targets vascular endothelial cells, in the interface tissue by immunohistochemical procedure.