Objectives: Platelet Rich Fibrin is autologus membranes which can be used for augmenting bony defects . The aim of this study is to evaluate and assess the regenerative power of Platelet Rich Fibrin (PRF) to be used in regenerative treatments of intra bony defects. Material and Methods: Twenty Wister albino male rats of 7 to 8 months old weighing ;350 g, were included in the current study. Bilateral defects were surgically induced related to the first maxillary molar. The right side was treated with PRF while the left side was used as control without PRF application. Bony defects of 3mm width , 2mm height and 1mm depth were created using a water cooled low-speed motor with a 1-mm-diameter round diamond bur. Each animal was considered to be its own control. Results: Histological examination of tissue sections revealed an overall osteogenic activity either on the PRF side or on the control side.Bone formation started earlier in specimens treated with PRF membranes and progressed at a somehow faster rate than that seen on the control side. By the end of the sixth week, fully developed bone trabeculae are observed , the PRF side exhibiting more mature and thicker bone trabeculae than that seen on the control side. Conclusion: PRF membranes represents a possible alternative to bone grafting as it enhances bone formation as well as better soft tissue healing