Background: Prosthetic treatment of the posterior edentulous maxilla may require bone augmentation to enable the placement and integration of dental implants. This constitutes a complex healing situation, and resorption of the grafted bone and failure of the implants often occurs. The application of platelet-rich plasma (PRP) has been suggested to improve incorporation and preservation of bone grafts. Objective: The objective was to assess the effectiveness of PRP on the implant failure and complication rate, when used as an adjunctive material with bone graft in sinus floor augmentation. Method and Materials: An electronic search of two databases (PubMed and Cochrane) was performed to identify randomized controlled trials (RCTs) in patients requiring sinus augmentation and implant placement in the posterior edentulous maxilla with or without using PRP as an adjunctive material to the bone graft. Data were extracted independently by two reviewers. The Cochrane tool was used for assessing the quality of included studies. Meta-analysis was performed for the included RCTs. Results: Nine RCTs were identified, four of which were included in the study. Three of these trials were judged to be at unclear risk of bias and one was at low risk of bias. The meta-analysis revealed no difference between the PRP versus non-PRP groups regarding implant failure and complication rate. Conclusion: The meta-analysis revealed no statistically significant difference regarding implant failure and complication rate of implants placed in the atrophic posterior maxilla with sinus floor augmentation with or without PRP as an adjunctive material to the bone graft. This finding should be interpreted with great caution given the serious numerical limitations of the included studies. Keywords: dental implants, implant failure, meta-analysis, platelet-rich plasma, sinus augmentation, systematic review