Background: this study is designed to assess the relationships between the thickening of the maxillary sinus membrane and the condition of the nearby maxillary teeth by CBCT. Materials and methods: CBCT images were assembled from 150 Egyptian patients. The maxillary sinus membrane thickness exceeding 2 mm is considered a pathologic membrane. Demographic data such as age and sex were recorded, as well as sinus membrane thickness, and the health condition of the adjacent teeth was noted down, classified, and investigated. Results: In the current study, the mean mucosal thickening of the maxillary sinus was 24.8±6.4 mm. Intra-class correlation coefficient (ICC) has shown nearly perfect agreement between observers for assessment of the mucosal thickening of the maxillary sinus (ICC= 0.9997) with a mean difference of -0.0099±0.15 (P=0.4195). Inter-observer agreement for the presence of dental caries, periodontal disease, periapical pathosis, and endodontic treatment was perfect (κ=1.0000). Conclusion: The results of this study showed that the prevalence of MT is directly correlated with age, the existence, and severity of a periapical lesion, and is higher in males