This case study reviewed conventional root canal treatment of a maxillary first premolar which unexpectedly had a single canal with two foramens. this tooth was recognized as the least frequent tooth appeared neither with additional canal nor unusual root anatomy. Retreatment for this casewas successfull through widening of the access cavity and the root canal. While trying the master cone, it revealed that the canal splitted and had two foramens. A thorough knowledge of the root canal anatomy as well as careful radiograph interpretations were essential in enhancing the root-cleaning procedure.