Several methods are used for periodontal regeneration and alveolar ridge reconstruction. This study aimed to compare the bone regeneration capacities of MinerOss X, Bio-Oss, and autograft in rabbit calvaria. In this animal study, four defects measuring 8 mm in diameter were created in the calvaria of 10 rabbits using a trephine bur. Three defects were randomly filled with MinerOss X, Bio- Oss, and autogenous bone. The fourth defect remained empty as a control. The rabbits were sacrificed after 4 or 8 weeks. Calvarial samples were taken and histopathologically evaluated. The mean number of osteoblasts and the amount of newly formed bone in all groups were higher at 8 compared to 4 weeks. At 4 and 8 weeks, the amount of newly formed bone and number of osteoblasts and osteocytes in MinerOss X group were significantly greater than the corresponding values in other groups, and MinerOss X was superior to Bio-Oss and autograft in all the assessed variables at both 4 and 8 weeks (P .001). Within the limitations of this study, the results showed that the number of osteoblasts and osteocytes and the amount of newly formed bone in the MinerOss X group were higher than those in Bio-Oss and autograft groups. However, further clinical studies are warranted.