Objective: The aim of the present study is to clinically and radiographically evaluate the treatment of human intrabony periodontal defects by using equine bone xenograft alone (Bio-Gen) in comparison to its combination with platelet- rich fibrin (PRF) membrane  in aggressive periodontitis  patients. Patients and Methods: A total of ten  patients with aggressive  periodontitis were selected for this study. Selected cases  utilized asplit mouth design and  were divided as follows : Group(I)(study group I ):This group comprised of ten aggressive periodontitis  patients with ten periodontal intra bony defects in one sidewhich were treated with equine bone granules alone. Group(II)(study group II):This group comprise of ten  aggressive periodontitis patients with contralateral defects which were treated by equine  bone granules in addition to  platelet rich fibrin which served as a membrance . . Initial therapy was performed for all patients,which consisted of full mouth scaling and root planing,oral hygiene instructions which were in the form of ooth brush instructins and the use of chlorhexidine mouth wash  and an occlusal adjustment when indicated. The scaling and root planing procedures were performed by using hand instruments and ultrasonic instrumentation.Local anesthesia was used for patient comfort.Plaque control was assessed at each scaling and root planing session,and oral hygiene instructions and motivation were reinforced. Four to six weeks following completion of the initial therapy,an evaluation of the periodontal indices  examination was performed to start the surgical phase. Clinical parameters used in this study included; plaque index (PI), gingival index (GI), papillary bleeding index (PBI), probing pocket depth (PPD) , clinical attachment level (CAL),and bone level by using cone beam . These parameters were recorded for all selected patients to provide clinical evaluation of periodontal status at the beginning of the study (baseline), after 3 and  six months . Results: The clinical results of both groups showed  that there was no significant difference By comparing GI,PI,PBI,PD,CAL and Bone Level between groups I & II between the mean values (P ≤0.05),at base line,3 months and at 6 months after surgery . Conclusions:Scaling and root planning (SRP) was effective in improving clinical parameters in patients suffering from aggressive periodontitis. the use of PRF, as the sole grafting material in periodontal osseous defects, is an effective modality in promoting a clinical resolution. Bio-Gen has the ability to augment the effects of PRF in reducing pocket depth, improving clinical attachment levels and promoting defect fill.