From August 1999 to June 2000, a cross-sectional analytic study was conducted in health check up clients to compare body mass index (BMI) and health risks data derived by measuring height, weight, and blood pressure, recording physical and laboratory outcome, and interviewing health characteristics. Data were analyzed for the relationships between BMI and lipids, and fasting blood sugar, and serum glutamate-pyruvate transaminase, and hemoglobin, and hypertension and other health risks and test for association by Chi-square test. The results showed that 1350 health checkup clients were 25.8 per cent overweight and 7.3 per cent were obese. There was a gradient relationship of abnormal cholesterol levels (>300 mg%) and levels of BMI. The abnormal triglyceride levels (>300 mg%) were higher in obesity than normal BMI (9.1% vs 1.6%). Hyperglycemia in obesity was higher than that of normal BMI (30.3% vs 11.6%). The percentage of two-fold abnormal SGPT levels (>76 units/L) in obesity (9.1%) was higher than that of normal BMI (2.8%). The percentage of anemia in underweight (28.3%) was higher than that of normal BMI (24.3%). Normal blood pressure in normal BMI (94.2%) was higher than that of obesity (69.7%).