Sufficient knowledge on the root and root canal anatomy is essential for practicing root canal treatment. The mesiobuccal roots of maxillary molar teeth present an endodontic challenge due to their wide variability and complexity of their internal morphological landmarks. A review on the literature indicates that the prevalence of a third mesiobuccal root canal in the mesiobuccal root of maxillary molar teeth may reach 9%, and the root canal configuration usually is type XV (3-2). These reported data reveal the importance of absolute awareness for this anatomical aberration that requires special attention from dental practitioners while commencing root canal treatment in maxillary molar teeth. Hence, this article aims to report and describe the management of a maxillary first molar tooth with three mesiobuccal root canals, but with an unusual configuration.