Context: Accessory mental foramen is a rare anatomical variation. Even so, in order to avoid neurovascular complications, particular attention should be paid to the possible occurrence of one or more accessory mental foramen during surgical procedures involving the mandible. Case report: A 3-dimensional computed tomography (3D-CT) scan of a female patient revealed an accessory mental foramen on the right side of her mandible. Conclusion: A 3D-CT scan should be obtained prior to mandibular surgeries so that the presence of accessory mental foramen can be detected, and so that the occurrence of a neurosensory disturbance or hemorrhage can be avoided. Although this anatomical variation is rare, it should be kept in mind that an accessory mental foramen may exist.