ObjectivesThis study was designed to provide recent trends of obesity among workers in Korea, and identify whether there was difference across occupational group.MethodsWe used data from Korean National Health and Nutrition Examination survey phase I to VI (1998–2015) to analyze trends in prevalence of obesity in Korean adult workers. Obesity was defined as a BMI of 25 kg/m2 or higher. Occupation was classified into 3 groups; a) non-manual worker, b) service/sales worker, c) manual worker.ResultDuring the period from KNHANES phase I to VI, the prevalence of obesity in male workers increased in all occupations as a whole (31.1% to 39.5% in manual worker, 32.3% to 38.2% in service/sales worker, 25.3% to 39.7% in manual worker). In contrast, female workers did not show a particular tendency except for a significantly decreasing in the prevalence rate in service/sales workers (30.8% to 23.9%, p for trend 0.0048).ConclusionsThe trends of obesity prevalence by gender and occupation were different. Especially for male manual-workers, the prevalence rate has increased steadily during the period, while it has decreased steadily in female sales/service workers. These results can be used to select vulnerable groups that can be applied to obesity prevention programs first.