Purpose: This pilot study evaluated and compared the degree of new bone formation following maxillary sinus graft using three different bone graft materials. Materials and Methods: Patients with an edentulous posterior maxilla (unilateral or bilateral) were included in this study and underwent a two-stage procedure. Each sinus was randomly assigned one of the three graft materials: anorganic bovine bone mineral (ABBM), anorganic equine bone mineral (AEBM), or mineralized cancellous bone allograft (MCBA). Bone core samples were obtained from the lateral wall of the grafted sites at least 8 months after maxillary sinus graft. Bone quality was evaluated during bone core retrieval. The samples were histomorphometrically analyzed using Kruskal-Wallis and Dunn-Bonferroni tests at the significance level of α = .05. Results: A total of 28 sinuses (14 unilateral and 7 bilateral) from 21 subjects, with a mean age of 61.5 (range: 33 to 75) years, were included in the study. Twenty-eight bone cores (ABBM [n = 9], AEBM [n = 9], and MCBA [n = 10]) were obtained at a mean healing time of 9.1 (range: 8 to 12) months. Six maxillary sinus membrane perforations (≤ 5 mm) were noted and repaired during surgery (21.4%). Histomorphometric analysis of the harvested bone cores revealed statistically significant differences in the percentage of vital bone, residual bone materials, and connective tissue/marrow among the different graft materials (Kruskal-Wallis; P .05). The percentage of vital bone in the MCBA group (32.0% ± 12.4%) was significantly greater than those in the ABBM (10.9% ± 8.9%) and AEBM (9.1% ± 5.9%) groups (P .05). The percentage of residual bone materials in the MCBA group (5.5% ± 5.7%) was, however, significantly less than those in the ABBM (34.3% ± 12.1%) and AEBM (38.9% ± 5.3%) groups (P .05). There were no significant differences in the percentage of vital bone and residual bone materials between ABBM and AEBM (P = 1.0). Newly formed bone and residual graft materials were integrated into the surrounding tissue with no sign of inflammation or foreign-body reaction. Conclusion: Within the confines of the study, MCBA has significantly greater new bone formation than ABBM and AEBM. AEBM showed comparable histomorphometric results in all parameters (percentage of vital bone, residual bone materials, and connective tissue/marrow) to ABBM. Keywords: bone formation, bone graft materials, histomorphometric analysis, maxillary sinus graft