It is well known that mandibular second molar root canal anatomy varies greatly.The present case report describes the variation in second mandibular molar .Variation may not always take the shape of additional canals; it may also take the form of fewer or smaller canals than what is typical. When the pulpal floor was examined with an endodontic explorer, a single round hole was visible in the floor of the pulp chamber. To confirm the existence of an independent single canal, many angulated radiographs were taken. Until F5, ProtaperNiTi instruments (Maillefer, Dentsply) were used for individual canal preparation. Obturation was accomplished using the lateral condensation technique and the sealapex sealer. A successful root canal procedure depends on knowing how many root canals are present in the tooth. Some teeth may have more canals than usual, while others may have less canals than usual. A solitary canal in the second tooth on the mandible should be quickly identified. By removing the necessity to remove unnecessary tooth material in order to find additional canals, single canal identification aids in the preservation of tooth structure.