This study aimed to analyze the prevalence of radix molaris in a subpopulation of Brazil's Northeast region using cone-beam computed tomography (CBCT). A total of 1092 CBCT exams and 3315 teeth (1541 first and 1774 s mandibular molars) were analyzed in axial, coronal, and sagittal planes using the PreXion 3D Viewer software. The teeth morphologies were analyzed and the occurrence of radix molaris, location, tooth, type (entomolaris and paramolaris) and patients' gender were recorded. The data were expressed in the form of absolute and percentage frequencies and statistically analyzed using Pearson's Chi-square test (P < .05). Fifty-nine patients (5.40%) and 71 teeth (2.14%) presented radix molaris, which was most frequently identified in first mandibular molars (2.92%) than in second mandibular molars (1.47%) (P < .05). No significant differences in the occurrence of radix molaris considering the gender of patients (36 women [5.22%] and 23 men [5.72%)] were observed (P > .05). It was observed that 92.96% of the teeth affected by the anatomical variation studied were classified as radix entomolaris. The bilateral prevalence of radix molaris was approximately 20.34% of the cases involving only first molars (P < .05). The occurrence of radix molaris was higher in first mandibular molars, regardless of the gender of patients.