Recently the calvarium has become a popular site for harvesting bone grafts because of its low incidence of morbidity, its proximity to the operative site, and the decreased amount of resorption as a result of its membranous nature. However, information regarding the phenomenon of repair at the donor site itself remains lacking. This investigation was initiated in 40 adult white New Zealand rabbits as an experimental model to study the process of repair at the donor site and to examine the possible use of hydroxyapatite to reconstruct the residual donor site deformity. Our experimental protocol closely followed our clinical procedure for the harvesting of split calvarial bone grafts. Our conclusions in the rabbit model were: (1) each of the commonly used hemostatic agents (bone wax and gelfoam) inhibit osteoneogenesis to varying degrees, (2) hydroxyapatite shows promise in the reconstruction of the donor site defect, and (3) if the periosteum comes in direct contact the defect repairs itself.