For the estimation of prevalence state of major chronic adult disease and their relationships with drinking and smoking habits in the Korean employees, we analyzed a medical check-up data of 155,799 subjects that was accumulated during the year of 2008. In age and sex distribution of the sample, male subjects were 106,229 and female 51,827 showing the ratio of 2:1 and the majorities were 30s and 40s covering 70.7% of the total. The prevalence rates of major chronic diseases were obesity 29.8% (male 38.3%, female 12.3%), hypertension 4.1%, HBV carrier inactive 3.3%, diabetes mellitus 2.9%, hypothyroidism 1.7% (male 1.3%, female 2.4%), hyperlipidemia 1.1%, hyperthyroidism 1.4% (male 1.1%, female 2.1%), osteoporosis 1.4% (male 1.4%, female 1.4%), anemia 0.9% (male 0.3%, female 2.0%) and renal disease 0.9%. The frequency of and volume of drinking in male group were 4.6 times and 7.5 times higher than female group respectively. The 33.8% of the workers were smoking currently. In the serological tests, all the items such as AST, ALT, ${\gamma}-GTP$, LDH for liver function, Cholesterol, TG, uric acid for hyperlipidemia and BP systolic, Fasting blood sugar, BMI for metabolic syndrome were significantly higher in the more drinking and more smoking groups than other groups (p<0.001). The higher prevalence rates in male group in the liver disease seems to be strongly related with the drinking and smoking habits in male employees. We suggest that employees should rather relying on leisure or hobbies than drinking and smoking for the stress relief.