In this study the outcome of autologous bone cell transplantation in artificial femur defects was tested within an animal study in sheep. The bone cells were harvested by a small ilium biopsy and cultivated in an individual medium with 10% autogenous serum and 90% X-Vivo 10. After two weeks 4 millions of the cultured bone cells were transplanted in artificial femur defects with bone gelatin as carrier. The remaining cells were characterized by various tests (Alkaline phosphatase, osteocalcin, collagen type I, calcification). This procedure was tested in 24 adult male sheep. The side of transplantation was randomized by plan. The corresponding femur side represents the control side. After 10 days, 4, 8 and 12 weeks animals were killed and the femura were taken for the following evaluation: histology, radiology, bone density and mechanical testing. The results show that the autologous bone transplantation leads to a significant higher bone regeneration in the bone defects. After ten days there was a lower migration of inflammation cells. After 4 weeks we find a significant increase of new bone formation on the transplanted side in the histological examination. After 8 weeks this significant difference was found even in the bone density. This difference increased in the 12 weeks group further on. The autogenous bone cell transplantation in the described way seems to be an potent method in the treatment of bone defects.