Objectives: This paper was for studying the features of perspiration according to Sasang constitution and to be helpful to make a diagnosis Sasang constitution. Using the result of this study, it will be helpful to diagnose a Sasang constitution. Methods: There were 504 patients(214 men and 290 women) who answered questionnaire and were diagnosed by the Sasang constitution specialist at constitutional clinic of Dongguk Bundang Oriental Hospital. Using the response of questionnaire and several statistical techniques, we tried to find the characteristics of each constitution depending on its sweat behaviors. Results: As a result of the analysis of questionnaire, Taeumin and Soyangin had, on the average, more sweat than Soeumin(p<0.01). In a view of feeling after sweating, Taeumin and Soyangin feels more fresh than Soeumin who feel tired(p<0.01).