The long term success of an endodontically treated tooth depends on the elimination of micro-organisms and creation of an apical seal. There is evidence of a high frequency of missed canals in unsuccessful cases requiring endodontic retreatment, which raises concerns about the possible detrimental impact of untreated canals on the result of a root canal treatment. During root canal therapy, it is possible for canals to be overlooked due to a lack of knowledge of the intricate root canal system. These untreated canals may encourage the growth of microorganisms that worsen post-operative discomfort and impair prognosis. In this paper, a case series of management of premolars with three root canals is discussed.