Human mandibular premolars have earned the reputation for having an extremely complex root and root canal morphology. The incidence of multiple roots and canals in mandibular second premolars is lower than those in mandibular first premolars. Mandibular second premolars with three root canals and separate foramina are very rare. In this case report, endodontic management of a three-rooted mandibular second premolar is discussed.