Mandibular canines are usually considered to be single-canal teeth. However, more than one canal and, more rarely, two roots may also occur. Three clinical cases are reported in order to illustrate endodontic anatomical variants in the human mandibular canine. All procedures were performed in conformity with the current state-of-the-art practices in endodontics, which included effective local anaesthesia, rigorous clinical and radiographic pre-access analysis, appropriate tooth restoration to ensure watertight rubber dam installation and surgical microscopic manipulations for precision. The first case involved a mandibular canine with only one root but two canals, including a lateral canal. The second case was a retreatment of a mandibular canine with two roots, two canals and a broken stainless steel K-File in the buccal canal. The third case involved a mandibular canine that revealed a rare root canal configuration (1-3-1): a Sert and Bayirli's type XVII canal. To avoid missing the presence of any root canals in endodontic treatment, clinicians should have a thorough knowledge of the anatomic variants of the root canal system and should take the necessary time to perform a rigorous pre-access analysis. The systematic use of a surgical microscope and ultrasonic endodontic tips facilitates and standardises access cavity preparation and canal localisation. Schlagwörter: endodontic anatomy, mandibular canine, pre-access analysis