Pure-phase beta-tricalcium phosphate(${eta}$-TCP) proved to be a bone regeneration material, providing the patient with vital bone at the defect site in a reasonable time, making a second surgical procedure for bone harvesting unnecessary. This study compares bone healing and BMP 2/4 expression in cranial defects in rabbits grafted with autogenous bone and ${eta}$-TCP. Thirty New Zealand White rabbits was divided into 3 group of 10 animals each. Bilateral calvarial defects were made in the parietal bones of each animal. ${eta}$-TCP placed in one defect and the other defects was filled with autogenous bone. The animal were sacrificed at 4, 8 and 12 weeks. Immunohistochemical analysis was used to investigate the expression of BMP 2/4. 1. The new bone formation around autogenous bone from 4 weeks and ${eta}$-TCP from 8 weeks. 2. In autogenous bone graft, BMP 2/4 expression was decreased from 4 to 12 weeks. 3. In ${eta}$-TCP graft, BMP 4 expression was increased from 8 to 12 weeks. But, BMP 2 was observed from 12 weeks. This study showed that bone healing, regeneration and, BMP 2/4 expression are delayed in grafted ${eta}$-TCP than autogenous bone.