OBJECTIVES: This study was carried to survey obesity and to screen high risk working processes related to obesity in the workplace. METHODS: In 1999, a total of 12,518 workers (men 8,379, women 4,139) residing in Daegu underwent an annual health examination at the Dongsan Medical Center. Grade of obesity was classified using body mass index (BMI) according to the following criteria; underweight ( <18.5), normal (19-22.9), overweight (23.0-24.9), mild obesity (25-29.9), severe Obesity ( >30.0). One industrial hygienist classified the working processes. RESULTS: The BMI mean and standard error was 22.63+/-0.03 in men and 22.18+/-0 . 0 4 in women. Age was a strong indicator of obesity, which peaked at 50-54 years old in men and over 60 years old in women. After adjustment for age by ANCOVA, the working process showing the highest BMI for men was 'Sales', at 23.93+/-0.18 while the lowest was 'Mill rolling', at 21.49+/-0.27. For Women 'Foundry Molding', at 22.84+/-0.49 was the highest while 'Office work', 21.78+/-0.12 was the lowest. CONCLUSIONS: Physical activities at work were inversely related to BMI in men but, were directly related in women. Women, over 50 years old and working in the process demanding high physical activity were the group most susceptible to obesity.