Background and objectives: An effective factor in choosing the correct place for the dental implant and performing surgical procedures in the posterior regions of mandible is the position of the mandibular canal. Failure to consider this important landmark will damage the inferior alveolar nerve. Considering the widespread use of implants and the precision of the images obtained from CBCT. The aim of this study was to evaluate the rate of visibility of mandibular canal by CBCT in order to prevent damage to the inferior alveolar nerves and arteries. Methods: In this study, 90 archived CBCT images of patients from a private center of oral and maxillofacial radiology in Yazd that was taken by technician was evaluated during 2012-2019. The visibility of the mandibular canal in reconstructed panoramic images of CBCT was assessed by a dentistry student trained by the maxillofacial radiologist in five areas in different thicknesses on each side. Data were analyzed using SPSS 17 software. Chi-square, and correlation coefficient were done. Results: In total, in 53.38% of CBCT images both borders of mandibular canal were visible, in 17.95%, only one border was visible (difficult observation) and in 28.7% of cases, lack of visibility of mandibular canal was reported. There was no significant difference between sex, age, side and thickness in mandibular canal visibility (P >0.05). Conclusion: In more than half of CBCT images, both borders were clearly visible in both right and left sides; therefore we can conclude that CBCT is a useful tool for the observation of mandibular canal before surgeries.