Objectives: This paper was for studying the features of stool 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 stool behaviors. Results: As a result of the analysis of questionnaire, the stool of Taeumin and Soyangin got, on the average, more scattered than the stool of Soeumin(p<0.05). In a view of defecation time, feeling after defecation and thickness of stool, there was no difference between Sasang constitution.