This research analyzed the hematological index and health related habits such as alcohol drinking, smoking and exercise, by classifying 539 middle-aged men (age: 40 - 59) into a normal weight group, an overweight group and an obese group, according to BMI (body mass index). As a result, 33.6% (n = 181) of subjects had a BMI of 23 or less and 30.2% (n = 163) were overweight and 36.2% (n = 195) were obese (BMI > 25). The average systolic/diastolic blood pressures of total subjects were 130.96mmHg and 80.38mmHg, respectively. And the average pressure of normal subjects was 126.85/77.57mmHg, which was significantly lower than in overweight and obese subjects. Diastolic blood pressure shows significant differences among the three groups. The overall average cholesterol level of normal subjects was 193.81mg/dl, which was significantly lower than those in overweight subjects. Those in obese subjects were significantly higher than in overweight subjects. The GOT (glutamic oxaloacetic transaminase), GPT (glutamic pyrutic transaminase), ${gamma}$-GTP (gamma-glutamyl transpeptidase) levels of obese subjects were significantly higher than in the overweight subjects. Frequency of alcohol drinking showed no significant difference among the groups. The smoking ratio in the obese group was higher than in the normal and overweight groups. The ratio of smokers was 53.1 %, and the alcohol drinking ratio was 81.0% of the total subjects. The frequency of drinking showed significant correlations with systolic blood pressure (p < 0.05) and diastolic blood pressures (p < 0.01) and ${gamma}$-GTP (p < 0.01). The duration of smoking showed a negative correlation (p < 0.01) with diastolic blood pressure, total cholesterol and ${gamma}$-GTP. On the other hand, exercising frequency showed negative correlations with blood glucose, ${gamma}$-GTP and GPT(p < 0.01). These hematological indices were correlated with health related habits such as alcohol drinking, smoking and lack of exercise, and to be the cause of chronic diseases. Therefore, proper nutritional education is needed to establish advisable health related habits to maintain proper body weight. (J Community Nutrition 8(2): 63-68, 2006)