Abstract : This study aimed to identify the root and root canal morphology of maxillary first (P1) and second (P2) premolars in Japanese patients using computed tomography (CT). The subjects were 200 Japanese individuals (100 males, 100 females) who had undergone CT for investigation of oral pathologies in the Department of Radiology at our hospital. For all subjects, one root was present in about 80% of P1 and >90% of P2. Using Turner's classification, one root and one apex were observed in about 50% of P1 and >90% of P2 in both sexes. P2 never showed a complex root in females, but two complex roots were observed in males. P1 predominantly (about 83%) showed two root canals, however, P2 predominantly (about 70%) showed one root canal. In addition, two root canals were more frequent in P1 than in P2 in both sexes (p<0.01). Using Vertucci's classification of the anatomy of one root in P1 and P2, two root canals in P1 were mostly Type Ⅳ (two root canals did not join in the morphology of two root canals and two apical foramina) or Type Ⅱ (two root canals joined in the morphology of one root canal and one apical foramen).