Platelet-rich plasma is an autologous product that is derived from whole blood through the process of gradient density centrifugation. The aim of this study was to determine the effect of PRP on healing of tibial bone defect in rabbit. In this study, 24 female adult New Zealand rabbits were used, and divided into two groups (I and II) of 12 rabbits each, according to the procedure performed. After general anesthesia, a hole in size of 1×4 mm in diameter and depth was created in the middle of the right tibia shaft with low speed dental bit. In group I defect was left empty and the rabbits in this group received no PRP. In group II defect was filled with autogenous PRP gel. 50 days after surgery, the rabbits become Euthanasia. Then bone defect was evaluated by means of histoMorphometrical factor. Histomorphometrical evaluation showed that the percentage of bone formation in group 2 was equivalent to 72.59±0.35 which was higher among other group. The results show that platelet rich plasma can increase the bone healing in middle shaft of tibia defect in rabbit
