Background: Errors that occur during root canal treatment can be caused by lack of information about the anatomical conditions of the root canal system. The purpose of this study was to examine the root and ca-nals morphology of mandibular anterior teeth using cone-beam computed tomography (CBCT). Materials & Methods: In this descriptive analytical study, 165 CBCT images of mandibular anterior teeth of patients from 15 to 60 years in the archives from oral & maxillofacial radiology department in 2015-2021 were used. CBCT images were examined in three axial, sagittal and coronal sections and the infor-mation of each tooth were recorded in pre-prepared forms. The data were analysed by Chi-square and Fisher exact test (α=0.05). Results: All mandibular central teeth were single-rooted, of which 59.7% were single canal and 40.3% were double-canal. 99.4% of the mandibular lateral teeth were single-rooted and 0.6% of the teeth were double-rooted. 62.8% of single-rooted laterals had a single-canal where 37.2% had double-canals. 97.6% of canine teeth were single-rooted and 2.4% of teeth were double-rooted. In single-rooted teeth, 95.3% had a single-canal. In mandibular single-rooted anterior teeth with two canals, Vertucci type III was the most common configuration. The frequency distribution of the variation of mandibular central and lateral teeth canals between women and men were not statistically significant, while in single-rooted canines significant differ-ences were observed (p= 0.031). Conclusion: Anterior teeth with two roots was not common. It was more prevalent in canines, laterals and central teeth. The prevalence of single-rooted mandibular teeth with two canals was mostly seen in central, lateral, and canine teeth. پرونده مقاله