Worksite health promotion programs have been associated with reductions in health risks but are labor-intensive and costly to implement. Therefore, innovative strategies to provide a cost-effective approach to health education program are needed. The purpose of this study was to investigate the effects of a worksite on-line health education program by email on metabolic syndrome risk factors and dietary intakes in male workers with metabolic syndrome. Anthropometric and biochemical parameters were measured and the nutrient intakes were assessed through FFQ. The diagnosis of metabolic syndrome was adapted from NCEP-ATP III with blood pressure, fasting blood glucose, triglyceride, HDL cholesterol, and Asia-Pacific definition with waist circumference. The education group consisted of 212 male workers and the non-education group of 236 age-matched male workers. The on-line health education program provided 10 sessions by e-mail. After a worksite on-line health education program, systolic blood pressure (p < 0.001), diastolic blood pressure (p < 0.001) and fasting blood glucose (p < 0.001) were significantly decreased and HDL cholesterol (p < 0.001) was significantly increased in the education group. Intakes of total energy (p < 0.05), carbohydrate (p < 0.05), sodium (p < 0.05) were significantly decreased in the education group, but there were no significant differences in dietary intakes in the non-education group after a worksite on-line health education program. The results indicate that online health education program by e-mail is effective for improving metabolic syndrome risk factors and dietary intakes in male workers and show potential for use in the working setting.