Purpose: Placement of endosseous implants in the atrophic maxilla is often restricted because of the lack of supporting bone. In this article, augmentation of the maxillary sinus floor with deproteinized bovine bone to enable insertion of endosseous implants is described. The technique is aimed at providing a cortical layer on top of the graft to ensure a reliable seal of the maxillary sinus and to achieve optimal stability of the bone graft in case of simultaneously placement of dental implants. Methods: The procedure was used in 200 patients (839 implants), using deproteinized bovine bone. The mean follow-up was 28.5 months. No inflammation of the bone grafts nor of the maxillary sinus occurred. The patients received implant supported overdentures or bone-anchored bridges. Results: The survival rate of implant restoration of this study was 97.6%. The total average of marginal bone loss in radiographs was $0.20{pm}0.38$ mm. Insufficient primary stability, bony quality, and infection were thought to be associated factors in the failed cases. Conclusion: This study documented that deproteinized bovine bone, when used as a grafting material for augmentation of the sinus floor, may lead to proper osseointegration of a endosseous implant.