Background: Many patients with heart disease continue to have cardiac events despite receiving optimal treatments for traditional risk factors. Consequently, non-traditional risk factors for heart disease, such as perceived stress, have attracted attention. Associations between perceived stress and plasma B-type natriuretic peptide (BNP) were explored, while controlling for traditional heart disease risk factors. Methods and Results: This cross-sectional study examined 360 male and 446 female (age, >40 years) residents of a rural Japanese community who received annual health checkups in 2006. A lifestyle questionnaire was used to obtain information regarding perceived stress and medical history, and routine anthropometric and blood pressure measurements and a laboratory assessment of cardiovascular risk factors, including plasma BNP concentrations and an electrocardiogram, were done. After adjusting for traditional heart disease risk factors, multiple regression analysis showed that perceived stress was associated with BNP concentrations, particularly in women (F=6.12, P=0.026). In addition, multiple tests using Bonferroni's procedure showed that BNP concentrations decreased with perceived stress level in men and women. Similar trends were observed in the sub-analyses of subjects with and without known heart disease. Conclusions: Perceived stress in our study was negatively associated with plasma BNP concentrations, independently of traditional heart disease risk factors. (Circ J 2009; 73: 1055-1061