Identifying the variations of root canal morphology is crucial prior to commencing any endodontic treatment. The advancement of current endodontic instrumentation and technology has greatly enhanced treatment outcomes, which are now more predictable. This clinical case report presents a case of a maxillary first molar showing six root canals and apical foramina, i.e. three mesiobuccal canals, two palatal canals and one distobuccal canal. The occurrence of bifurcation in the second mesiobuccal canal is also emphasised. Palabras clave: maxillary first molar, mesiobuccal canal, six canals, ultrasonic