Introduction: The aim of this study was to evaluate retrospectively the 3-year outcome of implants placed in augmented maxillary sinuses with minimal residual alveolar bone heights (<= 3 mm). Materials and Method: A total of 28 sinus floors were augmented with xenograft, and 58 implants were placed. The outcome measures were implant success based on implant stability and the absence of periimplantitis, and marginal and apical bone resorption on periapical radiograph and prosthesis survival. Results: Fifty-seven of 58 implants with their prostheses remained functional with a success rate of 98.28%. None of the implants showed any signs of mobility or periimplantitis. Both apical and cervical bone resorption around the implants were highest by the end of the first year. Conclusions: The success rate of the implants placed with staged approach in augmented maxillary sinuses with the residual alveolar bone height of <= 3 mm was high in a 3-year term. Bio-Oss is an acceptable substitute autogenous bone and can be used as an augmentation material during the maxillary sinus lift procedure.