This study examined labor force participation as a risk factor for coronary heart disease. The participants were 224 women aged 45 to 64, residing in a rural district in Japan. The working women spent a significantly greater number of working hours (paid and unpaid) and had a more "Westernized" food preference than homemakers. After adjusting for physical, psychosocial, and behavioral covariates, working women had significantly lower systolic blood pressure and blood glucose levels than homemakers. The "healthy worker effect" did not explain these differences. Middle-aged rural Japanese women who worked outside the home were slightly healthier than homemakers, despite their less healthy lifestyle. Total working hours were positively associated with systolic and diastolic blood pressures and total cholesterol in multiple regression analyses, which suggests that work overload has a harmful effect. A more suitable social environment is required if f Japanese working women are to enjoy a healthier life.