Background: Lateral sinus augmentation and simultaneous insertion of dental implants is a highlypredictable procedure and associated with high rate of implants success.Aims: To evaluate implant stability changes following maxillary sinus augmentation utilizing deproteinizedbovine bone alone or mixed with platelet-rich fibrin.Materials and Methods: A total of 34 lateral sinus augmentation procedures were performed and 50 dentalimplants simultaneously installed. The lateral sinus augmentation cases were allocated randomly into 3groups: Group A comprised 13 procedures and 21 dental implants utilizing solely deproteinized bovine bone.Group B involved 10 cases and 16 dental implants using deproteinized bovine bone mixed with leukocyteand platelet-rich fibrin. Group C included 11 operations and 13 dental implants employing deproteinizedbovine bone mixed with advanced platelet-rich fibrin. Resonance frequency analysis test was performedimmediately after implant installation and 24 weeks postoperatively for the measurement of the implantstability.Results: Implant stability quotient values increased significantly for all study groups 24 weeks after dentalimplants installation (P= 0.001). The implant stability quotient at T1 (day of implant installation) was 56.93±12.01 for group A, 58.34 ±12.82 for group B, and 61.35 ±8.47 for group C. The implant stability quotientat T2 (24 weeks after implant insertion) was 69.17 ±5.10, 69.43 ±5.32, and 68.50 ±7.44, respectively.Conclusion: The addition of leukocyte and platelet-rich fibrin or advanced platelet-rich fibrin to the bovinebone for sinus floor augmentation did not increased the implant stability quotient value in comparison to thebovine bone alone.