Objective: The aim of this study is to compare bone regeneration after implantation of both Bioresorb-classic (β–TCP) and Nanobone (NHA) in experimental osseous defects in rabbit tibia. Material and methods: Thirty New-Zealand white adult male rabbits were used. Sterile round burs no. 6 were used to create the critical sized holes in each tibia, two holes, 1 cm apart were created in each tibia reaching the bone marrow. Bioresorb-Classic was packed in the upper hole of the left tibia (sub group-B), Nanobone was packed in the upper hole of the right tibia (sub group-N), while the lower hole of right and left tibiae was left empty and used as a control group (sub group-C). The animals were divided into 3 main groups, 10 rabbits each according to the time of sacrification 2, 4 & 6 weeks recpectively. The experimental animals in each group were divided into two halves (5 rabbits each). The first half was used for histological and histomorphometric examination while the second half was used for DXA evaluation. Results: histological and histomorphometrically both Nanobone and Bioresorb-classic were osteoconductive graft material. They were capable of healing critical sized defects induced in rabbit animal model. Conclusion: Nanobone graft material exhibited enhancement in the rate and pattern of bone repair relative to both control and Bioresorb-classic defects.