Aim: The aim of this study was to evaluate available bone quality and quantity after performing maxillary sinus floor augmentation using Xenograft versus Xenograft/PRF combination.Patients and methods: This was a split mouth study conducted on eight patients. For each patient bilateral sinus floor augmentation was performed using xenograft in one side and xenograft/PRF combination for the other. Postoperative cone beam CT radiographs were performed 1 week and 6 months postoperatively to assess bone quantity. Second stage surgery was performed 6 months after sinus lift procedure. It involved implant placement and biopsy harvesting for histomorphometric analysis. Results: Histomorphometric and radiographic results showed no statistical significant difference between the two groups. Conclusion: PRF has no beneficial effect on graft maturation or negative effect on volumetric stability of deproteinized bovine bone. PRF membranes represent an easy and successful method to cover osteotomy window in sinus lift procedures. PRF/xenograft combination can be used as an alternative to the routinely used xenograft materials and collagen membranes reducing the quantity of bone substitute used and the cost of the procedure. Further studies are recommended for long term evaluation.