In this study, the perceptions of domain experts who participated in foresight activities on the impact on policy making are examined by conducting interviews and surveys on five previous foresights in Japan between 1996 and 2007. The purpose of the study is to examine how domain experts look at the practice of foresight in general, and perceive its overall impact on policy making in particular, in the setting of Japanese foresight conducted in the past 15 years. There are two tasks for doing that in this study: to know the views of scientists and engineers who participated in foresights on the impact of foresights they participated; and to know the effect of respondent’s characteristics on their perceptions on impact.