Bovine-derived bone mineral demonstrated good osteoconductive properties as grating material for maxillary sinus floor elevation, but the long-term behavior of this material has not been reported. The purpose of this report was to analyze and compare histomorphometric measurements of new bone, bone graft, and medullar spaces 6 months, 12 months, and 20 years after grafting. In the grafted area, the amount of mineralized bone was 16.96% at 6 months, 22.53% at 12 months, and 22.05% at 20 years, respectively. The amount of bovine-derived bone mineral ranged from 35.87% to 4.85% in the same period. The volume of the newly formed mineralized bone does not increase over time, conversely to nonmineralized bone. Keywords: bovine bone, histomorphometry, long term, maxillary sinus grafting