Tooth transposition is a rare positional anomaly that may create many orthodontic problems. Its etiology is an enigma. The occurrence of mandibular canine/lateral incisor transposition is a relatively rare anomaly. Two rooted canine/rotated incisor transposition has not been reported previously in the clinical dental literature. We describe a case with transposition of a mandibular two rooted canine and a lateral incisor with 180 degrees rotation. Possible causes such as trauma and tooth agenesis were absent in this case. Due to the root anomaly, we consider that our case may have a genetic etiology. Although the mandibular lateral incisor and canine were not in their normal anatomic positions, there were no functional or esthetic problems.