The present study investigated the relationship between an interview-based health promotion program and cardiovascular risk factors at manufacturing companies. Excluding insufficient data and the workers who took medication prescribed by a physician in 1993, the subjects were six hundred and twenty-nine 18-55-yr-old employees who had been working at two manufacturing companies in Kyushu from 1993 to 1997. The intervention company introduced an interview-based health promotion program from 1993. The program consisted of health measuring, group education, and health interviewing all employees to help with their behavioral change. We subdivided the subjects into younger (18-34-yr-old) and older (35-55-yr-old) groups. We defined changing degree (Delta) with (the following data in 1997) minus (the initial data in 1993). With agreement of the subject companies, we compared the Delta of each item, including body mass index (BMI), systolic blood pressure (SBP), diastolic blood pressure (DBP), serum total cholesterol (T-cho), serum aspartate aminotransaminase (AST), serum alanine aminotransferase (ALT), and serum gammaglutamyl transpeptidase (GGTP), in the intervention with that in the reference. BMI and SBP decreased significantly after the program in the under 35-yr-old intervention group. On the other hand, T-cho, AST, ALT, and GGTP decreased and HDL increased significantly after the program in the over 34-yr-old intervention group. Our results showed that the worksite health promotion had the potential to improve cardiovascular risk factors of Japanese employees.