1. Introduction This study aims to survey knowledge and attitude of Sasang constitution investigators on the Sasang constitution clinical study. 2. Methods We have made up list of 24 Sasang constitution investigators who have conducted Sasang constitution clinical study before. The study has been surveyed for 20 investigators who has been experiencing clinical study bye-mail or interview. 3. Results 1) The recognition degree on clinical study for sasang constitutional investigators was relatively lower than that for non-oriental investigators. 2) Most investigators have difficulty in designing a Protocol and they thought Protocol is most important in clinical study. 3) The investigators has stressed the need of diagnosis guideline on Sasang Constitution in performing clinical study. 4. Conclusions Special course of clinical study for sasang constitutional investigators should be prepared to activate Sasang constitution clinical study. This course may set up the guideline of sasang constitution clinical study and designing protocol. Also it is urgent to develop constitution diagnosis guideline for clinical study.