Background : The serum total cholesterol is supposed to be increased as dietary pattern is Westernized recently in our country. We studied the longitudinal change of serum total cholesterol levels in normal Korean adult male workers and analyzed the influence of age, weight, blood pressure, fasting blood sugar, lifestyle (exercise, smoking, alcohol drinking habits) on change of serum total cholesterol levels. Methods : The 6279 healthy adult male workers were studied during recent 10 Years (1992 and 2002). Those who suffered from hypertension, diabetes mellitus, ischemic heart disease, nephropathy, thyroid disease were excluded. Those who took antilipidemic drugs were al so excluded. Blood sampling for serum total cholesterol and sugar was done after overnight fasting for more than 12 hours. Data on lifestyle were obtained using self administered questionnaires. Result : The serum total cholesterol levels had increased by 23.223.60 mg/dL (2.32 mg/dL per year) between 1992 and 2002 surveys. The increment of serum total cholesterol levels was most prominent in twenties (3.30 mg/dL per year) during 10 years and less prominent in thirties (2.80 mg/dL per year), forties (2.19 mg/dL per year) and fifties (1.55 mg/dL per year). The change of body mass index (BMI) was most significantly correlated with that of serum total cholesterol level (r=0.290, p=0.0001) (=0.084, p=0.0001) The change of serum total cholesterol levels was also significantly correlated with age, diastolic blood pressure change, fasting blood sugar change, exercise and smoking habits. However, it was not significantly correlated with the alcohol drinking habits among influencing variables. Conclusion : The serum total cholesterol levels were increased by 23.223.60 mg/dL (2.32 mg/dl. per year) during recent 10 years. The increment of serum total cholesterol levels was most prominent in younger age group. The change of serum total cholesterol levels was most significantly correlated with that of body mass index (BMI) among influencing variables.