Purpose: Some variations of the mandibular canal (so-called bifid mandibular canal) have been reported using various radiography techniques; however, the occurrences of bifid mandibular canal were less than 1% according to panoramic radiographic surveys. The purpose of the present investigation was to clarify the rate and type of bifid mandibular canal in the mandibular ramus region, as observed using cone-beam computerized tomography (CBCT) images. Materials and Methods: One hundred twenty-two patients who had undergone preoperative imaging of dental implant treatment using CBCT were enrolled in the investigation. Two-dimensional (2D) images of various planes in the mandibular ramus region were reconstructed on a computer using three-dimensional visualization and measurement software. The course of the mandibular canal was observed and the length of the bifid canal was measured. Results: Bifid mandibular canal in the mandibular ramus region was observed in 65% of patients and 43% of sides. Bifid mandibular canal can be classified into four types: retromolar, dental, forward, and buccolingual canals. Conclusion: Bifid mandibular canal was observed at a high rate using CBCT. Keywords: bifurcation, cone-beam computerized tomography, dental implant, mandibular