The placement of oral implants into jaw bone has a high predictability provided an adequate bone volume surrounding the implant is present to ensure primary stability and resistance to functional loading forces after completion of osseointegration. In the distal area of the maxilla, an adequate bone volume is often lacking because of the proximity of the sinus cavities. The aim of this study was to evaluate histologically the simultaneous placement of endosseous implants into the sinus cavity and the surgical elevation of the sinus floor including filling the cavity with different grafting materials. In 9 sinus areas of 5 beagle dogs, 9 titanium implants (ITI® Dental Implant System( were placed, and the void space of the sinus cavity was filled simultaneously with either demineralized freeze‐dried human cortical bone (Musculoskeletal Transplant Foundation), resorbable hydroxyapatite (Osteogen®) or natural cancelleous bovine bone mineral (Bio‐Oss®). To study bone formation, fluorochrome markers (tetracycline HCI and calcein green) were used at 2 and 8 weeks. Clinically, all implants healed uneventfully, and 5 months after implant placement the dogs were killed for histologic evaluation. All implants exhibited osseointegration within the pre‐existing cortical bone of the sinus floor. The implants surrounded by freeze‐dried bone xenografts yielded no formation of new bone, whereas the sites with hydroxyapatite or natural bovine bone mineral demonstrated newly formed bone with direct contact at the implant surface. The average extent of bone to implant contact was 25%(SD= 10.6%) and 27%(SD=8.8%), respectively in relation to the length of the originally denuded implant surface. In addition, the bone markers revealed a rapid bone formation and remodeling, especially around natural bovine bone mineral particles. This study yields new bone formation with direct contact to the implants surfaces in the sinus cavity into which suitable grafting materials were placed simultaneously. Resorbable hydroxyapatite (Osteogena) and natural cancellous bovine bone mineral (Bio‐Oss®) were osteoconductive and hence were suitable for bone formation around endosseous implants.