objectives: The objective of this study was to assess the effect of using injectable platelet-rich fibrin (i-PRF) mixed with bovine bone in management of critical size bone defect. Patients and methods: The study was conducted on 14 patients (9 males and 5 females) presented with a cyst that occupies critical bone defect at the anterior region of upper jaw Split mouth technique was used in an attempt to limit variables. Clinical examination was made to all patients. Preoperative panoramic radiographs and cone-beam computerized tomography (CBCT) were taken for every patient to determine bone density. The change in bone density was measured using (CBCT) after 3 and 6 months of healing. The pain was scored. All readings were recorded and analyzed statistically. Results: There was a statistically significant difference between mean bone density in both groups at the 3rd and 6th months. The study group showed a higher density (335-502) than the control group (231-337). While There was a statistically decrease in the mean pain by VAS in the study group (1.57-.71) than the control group (2.43-1.29) in the 2nd 3rd week. Conclusion: Application of graft with the injectable form of platelet-rich fibrin (i-PRF) is very effective and promising on enhancing the healing process and decrease the time needed for healing than the graft alone.