Objective: The aim of this study was to assess the effect of a health promotion program with 2–3-month Internet or printed material support without a face-to-face intervention at a large-scale worksite. Methods: An uncontrolled intervention was conducted. In 2005, 22,429 employees underwent a health check-up and a lifestyle assessment. In 2006, 2,096 employees were recruited to participate in an intervention group (IntG), and the remaining 20,228 employees were allocated to a control group (ConG). After one-year follow-up, 1,888 employees in IntG and 15,474 employees in ConG were analyzed by Breslow's lifestyle index, overall prevalence of cardiovascular risk (OPCR) and 10% 10-year risk based on cardiovascular risk factors in 2007. Results: Breslow's lifestyle index (over 5 points) in IntG showed a higher OR (1.13 with a 95% CI of 1.01–1.26) than that in ConG. Compared with those with a poor lifestyle, the subjects who had maintained or improved their lifestyle showed a lower OPCR (OR 0.88, 95% CI 0.79–0.97; OR 0.84, 95% CI 0.74–0.95 [ p for trend=0.003]) and 10% 10-year risk trend (OR 0.38, 95% CI 0.31–0.47; OR: 0.29, 0.22–0.37 [ p for trend <0.001]). Conclusion: The present study showed that there was a modest lifestyle behavior change using a program without face-to-face contact. The employees who maintained and improved their lifestyle had a lower OPCR and 10% 10-year risk. Future study should increase the number of employees actively attempting to improve their lifestyles at a worksite.(J Occup Health 2013; 55: 74–83)