In order to study the relationship between life-style and serum lipids level in young adults, the author measured the concentration of serum total cholesterol (TC), triglyceride (TG) and high density lipoprotein cholesterol (HDL-C) and investigated age, relative weight, weekly alcohol intake and daily cigarette smoking through questionnaire in 310 male workers aged 20 to 39, in Ulsan area. The results obtained were as follows: 1. In the factors being able to influence serum lipids level there was negative correlation between age and alcohol intake, and the positive correlation between age and relative weight, alcohol intake and relative weight, alcohol intake and smoking with the strongest correlation between alcohol intake and smoking. 2. In univariate analysis, mean total cholesterol concentration were significantly different according to age, smoking and relative weight: mean triglyceride concentration were significantly different according to relative weight only; mean HCL-C concentration were significantly different according to alcohol intake alone. 3. In non-drinkers, HDL-C concentration of smokers were significantly lower than that of non-smokers but triglyceride concentration of smokers were significant higher. And in drinkers, total cholesterol concentration of smokers was significantly higher than that of non-smokers. 4. In multiple regression analysis, significant independent variables were relative weight, age and smoking in the total cholesterol concentration, and relative weight, age and alcohol intake in the triglyceride concentration, and alcohol intake, relative weight and smoking in the HDL-C concentration. By these independent variables, total variation in each dependent variable was explained 7.9%, 17.6% and 7.4% respectively.