Purpose: The aim of this study was to determine the effect of collagenated biphasic calcium phosphate (CBCP) loaded with fibroblast growth factor-2 (FGF-2) on bone regeneration in a rabbit sinus model. Materials and Methods: Bilateral sinus augmentations were performed using either FGF-2-loaded CBCP (FGF-2 group) or CBCP only (control group) in 10 rabbits. The experimental animals were euthanized at 2 weeks (n = 5) or 4 weeks (n = 5) postoperatively. Volumetric analyses were done by means of microcomputed tomography and histomorphometry. Results: The volumes of total augmentation, new bone, residual material, and fibrovascular tissue were significantly greater in the FGF-2 group than in the control group at 2 weeks, but the differences between the two groups had disappeared by 4 weeks. Histologically, the healing patterns, such as new bone formation and the resorption of residual material, did not differ notably between the two groups. The results of the histometric analysis did not correspond to those of the volumetric analysis. The areas of total augmentation, new bone, residual material, and fibrovascular tissue, and the number of blood vessels did not differ significantly between the FGF-2 and the control groups at either time point. Conclusion: CBCP loaded with FGF-2 resulted in the early promotion of new bone; however, it failed to produce superior bone regeneration in a later stage of healing. Keywords: animal model, bone regeneration, bone substitute, fibroblast growth factor-2, maxillary sinus