Purpose: The purpose of this study was to examine health problems and to estimate economic impact based on health problems of workers. Methods: The subjects of this study consisted of 301 workers who received a group occupational health service. Data was collected from February 1 to March 30, 2006. The questionnaire contained questions based on general characteristics and the Stanford Presenteeism Scale. Data was analyzed with descriptive statistics, t-test using SPSS program. Results: The primary health conditions as reported by workers were ranked in order as stomach or bowel disorders, back or neck disorders, or liver function disorders. The reason of absenteeism per worker was ranked in order as asthma, or a breathing disorder. The reason of presenteeism was ranked in order as asthma, insomnia or a sleep disorder. The cost of the total economic impact on the workplace in this study was 8,851,838 won. The cost of absenteeism per worker was 8,390 won. The cost of presenteeism per worker was 941,732 won. Conclusion: Presenteeism had a strong correlation to health conditions of the workers. Therefore, improving the work conditions of the workers is very important. If employers improve the health condition of workers, they will benefit from improved productivity in their business.