OBJECTIVE: The purpose of this study was to measure,analysis and compare the tooth size and arch length discrepancy of class l malocclusionas determined by bolton and carey for the chinese and indian (dravidian) ethnicity between the age group of 13 to 18 respectively.　　 MATERIALS AND METHODS: In this materialistic study with the retrospective analysis,total of 80 patients cast,40 cast (20 males and20 females) ofindian and (20 males and 20 females) of chinese were takenand measured the mesiodistal width of both upper and lower jaws andcephalometric analysis were done for the same, the indian record weretaken at Department of orthodontics meenakshi ammal dental collegechennai india and the chinese were taken in Department of orthodonticschongqing stomatology hospital affliated to chongqing medical uruversity.Chongqing, China.　　 RESULTS: In this nine parameters of cephalometric analysis sevenparameters came out to be significant both in males and females namelySNB, SN-POg, MP-SN, Y-Axis, U1-L1, Ul-SN and L1-MP. In respect tothe comparison between Chinese and Indians, Chinese were found to besignificant in all the parameters mentioned above. And in arch length toothsize analysis out of seven parameters four parameters proved to besignificant MD width of mandibular teeth, overall ratio and Mandibulararch length were significant in Indian males over Chinese males but infemales only MD width ofmandibular teeth proved to be significant.　　 CONCLUSION: Cepahlometric values are specific for each and everyethnic group. The normative data for Indian and Chinese population shouldbe used as a guide for diagnosis and treatment plan for orthodontist in theircountry.