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Objective: The aim of this study is to analyze the frequency of radix paramolaris (RP) and radix entomolaris (RE) in the first and second molars using cone beam computed tomography (CBCT). Materials and Methods: The CBCT images of a total of 400 patients at the ages of 14 to 66 were included in the study. On the images that were included, two maxillofacial radiologists simultaneously examined the presence of radix paramolaris and radix entomolaris by using axial CBCT cross-sections from the pulpal chamber towards the apical. Results: At least one RE or RP was observed in 36 of the 400 patients (9%). A total of 20 RPs (1.25%) were observed, including 2 bilateral and 16 unilateral cases. A total of 38 REs (2.38%) were observed, including 11 bilateral and 16 unilateral cases. There was at least one RE or RP in 16 of the 149 male patients (10.7%) and in 20 of the 251 female patients (8%). Conclusion: Consequently, while the prevalence and types of third root variations differ between different populations, RE is seen more frequently in mandibular first molar teeth, and RP is seen more frequently in mandibular second molar teeth. No significant relationship could be found between sex and the prevalence of third root variations in mandibular molar teeth images included in this study. No significant difference was found between the right and left sides as the localizations of RP and RE in terms of prevalence. Keywords: Radix entomolaris; Radix paramolaris; Root canal morphology; Cone-beam CT; Mandibular molar