The purpose of this study was to investigate the beneficial effects of particulate ostrich eggshell grafting on the healing of experimentally induced skull defects. The clinical, radiological, histological, and histomorphometrical findings of this material were compared with the results of commercially available demineralized bone matrix (DBM). The study was conducted on 18 adult New Zealand rabbits. One defect served as a control and the remaining ones either were filled with different sized eggshell particles or DBM, in each animal. Clinical and radiological inspections and histologic investigations of the animals were done at the 1st, 3rd, and 6th months of postoperative period. Radiologically, minimal bone regeneration was observed at the empty, control defect sites. The most advanced bone regeneration was in the DBM grafted defects. The eggshell particle grafted defect sites displayed weak bone regeneration at earlier stages, at 1st and 3rd months after operation when compared with demineralized bone matrix. Nevertheless, ossification was satisfactory at 6th month after operation when compared with the control defects. Within the limitations of this study, it was concluded that Ostrich eggshell powder (OSP) is a worth-while bone substitute because it is a safe, cheap, and easily available material. Long-term studies will clarify its possible role in maxillofacial surgery. Further sophisticated experiments should be undertaken before human implantation concerning its osteoproductive activity alone or in combination with other materials. © 2007 Wiley Periodicals, Inc.