We implemented a nationwide population-based study in Taiwan to compare the physical and biochemical parameters, diet and exercise lifestyles, and prevalences of diabetes, hyperlipidemia, and hypertension between males and females, and to clarify the determinants of diabetes, hyperlipidemia, and hypertension in Taiwan. In this cross-sectional study, 7,578 subjects were selected from the general population by stratified random sampling for the Surveillance of Taiwanese Civil Health in 2002. Blood samples were taken and information on body composition, demographics, exercise and dietary habits, and medical and drug histories were obtained from structured interviews administered by well-trained interviewers. A total of 6,600 subjects (87.1%), aged 15.6-95.0 years old, completed the survey. The overall prevalences of diabetes, hyperlipidemia, and hypertension were 9.9%, 22.8%, and 15.7%, respectively, and hyperlipidemia (27.0%) and hypertension (19.2%) were more prevalent in males. Males were more likely to have high-fat and high-cholesterol diets, compared with females. Although there were differences in the prevalences of hyperlipidemia and hypertension between the sexes, adjusted logistic regression analysis demonstrated little contribution of diet and exercise habits to the risks of diabetes, hyperlipidemia, or hypertension after adjusting for age, sex, waist-to-hip ratio, serum blood sugar levels, cholesterol, triglycerides, apolipoprotein A1, apolipoprotein B, glutamate oxaloacetate transaminase, glutamate pyruvate transaminase, creatinine, uric acid, and blood pressure.