Objective: The purpose of this study was evaluated to detect the effect of platelets rich fibrin (PRF) as a graft material for socket preservation in mandibular post extraction sites.Materials and Methods: Sixteen male and female patients, with the age range between 25 and 45 years, ten male and six female patients, Atraumatic extractions were done for 32 teeth. Sixteen sockets had immediate application of (PRF) after extraction, while the other sixteen sockets were left empty to serve as control. Sockets were closed by suturing and no membranes were used in both sides. Periapical x-rays were taken on dental periapical film as image receptor immediately after extraction then 3, 6, and 9 months after extraction. Films were then digitized using digital camera and entered into computer to use the Digora system for bone density and linear resorption measurements. The data were collected was statistically analyzed by Wilcoxon signed-rank test.(P=0.05).Results: There was no statistical difference between the PRF group and the control group at the base line. Starting from the 3rd postoperative month the PRF group had a statistically significantly greater bone density mean values at each time point till the end of follow up period. The mean and standard deviation values were (71.3 ± 8.3) to (70.9 ± 8.4) at base line, then after 3 months they were (79.7 ±7.1) to (75.8 ± 6.3),after 6 months (88.2 ± 6.6) to (81.7 ± 6.7), and after 9 months they became(96 ± 8) to (88.3 ± 8.1).Regarding the mean bone resorption, the control group showed statistically significantly higher mean bone resorption value than PRF group at base line. The mean and standard deviation values were 3.57 ± 1.7 mm in control group and 3.34± 1.7 mm in PRF group. Similar result was seen after 9 months as the control group had also statistically significantly higher mean bone resorption measurement than PRF group. The mean and standard deviation values of bone resorption measurements after 9 months were 4.60 ± 1.6mm in control group and 4.23 ± 1.6 mm in PRF group. Conclusion: the loss of alveolar ridge after extraction can largely be avoided by socket-preservation procedure using the Platelet Rich Fibrin (PRF) biomaterial. PRF proved to be an easy to collect, prepare and handle. It was also safe and cost effective biomaterial that may represent an alternative graft material to the currently available bone regenerative therapies used for ridge preservation.