This study was performed to delineate the relationship between lifestyle and nutritional risk factors associated with hypertension in representative middle-aged Korean population. Hypertension in this study is defined as hypertensive (SBP> or = 140 mmHg or DBP> or = 90 mmHg) adults without recognition of a disease state before a health exam. With data from the 1998 and 2001 National Health and Nutritional Survey, nutrient intakes of 6,112 adults, 40-64 years of age were calculated using food composition database and matched with health examination records by individual ID. After excluding those with extreme intake values, the number of final subjects included in the analysis was 5,200 (male 2,458, female 2,742). Using logistic regression method, socio-demographic data, lifestyle factors, and nutrient intakes were analyzed. Risky factors for hypertension revealed in this study were age, sex, BMI over 23, waist circumference, alcohol intake of more than 16 g (male) or 8 g (female). Regarding nutrient intakes, the intakes of highest quartile for energy (> or = 2363.0 kcal) and protein (> or = 90.2 g) were significantly associated with higher risk of hypertension after adjusting for age, sex, and other socio-demographic factors (OR = 1.312 (1.046-1.711), OR = 1.488(1.194-1.854), respectively)). Although high intakes of sodium (> or = 6604.0 mg) and phosphorus seemed to be risk factors of hypertension also before energy adjustment (OR = 1.278(1.034-1.581), OR = 1.280(1.024 -1.600), respectively), only high intakes of energy and protein remained significant after adjustment. This study revealed that modifying risky lifestyles and dietary patterns, especially high energy intake, high protein intake, and high alcohol drinking, in middle-aged Korean adults could result in a prevalence decrease and/or prevention of hypertension.