The efficacy of Bio-Oss as a graft material for sinus floor elevation was studied in 15 patients. A total of 20 sinus augmentation procedures was performed, and 6 months later 57 implants were placed into the augmented sinuses. New bone formation was confirmed in biopsies of 3 patients (new bone: 21.08% ± 7.25% after 6 mo, 27.55% ± 4.88% after 12 mo; Bio-Oss: 39.17% ± 4.36% after 6 mo, 27.01% ± 11.64% after 12 mo). After a mean loading period of 4.0 ± 0.5 years (range 3.2 to 4.8 y), 56 implants remained in place. This study confirms Bio-Oss's good osteoconductive properties.