An experimental study was carried out aimed at studying the short-term, mid-term and long-term biological features of the incorporation of homologous bone grafts. Homologous cortical and corticospongy grafts of the proximal third of the tibia were implanted in 60 adult New Zealand rabbits, under general anaesthesia. The animals were sacrificed after predetermined periods of time, and the tibia removed for radiographic and histological examination. An analysis of the different phases of the fusion process allowed us to observe the different dynamic evolution of osteogenic repair of cortical as compared to spongy grafts. This could be explained by the different tensile properties of the two types of grafts.