OBJECTIVES: This study was conducted to estimate the incidence of abnormal liver function and risk factors in male employees of an industry in Ulsan City. METHODS: Five hundreds and seventy nine male employees were selected as the study cohort and 533(92.1%) of them were followed after one year. The blood sample was collected to test for AST, ALT, gamma-GTP, total-cholesterol, fasting blood sugar and a self-administered questionnaire on life style was done. General characteristics(age, marital status, educational level), job department, exposure status for organic solvents, life style(alcohol, smoking, exercise, diet), past history of liver disease, family history of liver disease, drug intake, HBsAg, blood glucose, total-cholesterol were considered as risk factors. The result of liver function test after 1 year follow-up was treated as dependent variable. The operational definition of abnormal liver function was as follows; those who had abnormal liver functions in the two repeated tests with one month interval. RESULTS: The annual incidence of abnormal liver function was 9.6 per 100 and age-standardized incidence was 9.5. BMI, alcohol, past history of liver disease, and meat intake were significantly related to the incidence(p<0.05). In multiple logistic regression analysis, BMI(RR=2.70, 95% CI=1.41-5.16) and alcohol(RR=1.98, 95% CI=1.08-3.60) were proved as the significant variables. By stratified analysis considering changing pattern of alcohol and BMI, the relative risk of the BMI normal-normal and alcohol intake high-high group was 2.24(95% CI=1.09-4.62) and that of the BMI obese-obese and alcohol intake high-high group was 5.66(95% CI=2.69-11.88) compared with that of BMI normal-normal and alcohol intake low-low group. CONCLUSIONS: The age-standardized annual incidence of abnormal liver function was 9.5 per 100 in male employees. Thus, an active effort for reducing alcohol intake and controlling BMI should be done to reduce the incidence.