BACKGROUND: Our study was done to identify the risk factors of hypertension in order to implement primary prevention strategy in Korean healthy adults. METHODS: The subjects, who had received medical examination at the Health Promotion Center of Asan Medical Center from June 1990 to February 1991, were included in the Asan Cohort Study. A total of 1,329 men and 886 women were followed up to June 2000. The subjects who initially had hypertension or coronary heart disease or were diagnosed with hypertension within 1 year after study enrollment were excluded. Incident cases were ascertained through the chart review, telephone contacts, and follow up examination. During the follow-up period, 140 male and 76 female hypertension incident cases occurred. For each case one normotensive control was selected, matched on sex, age, and follow-up period. We used conditional logistic regression for matched pairs to estimate odds ratio. RESULTS: For men, daily alcohol intake, family history of hypertension and body mass index (BMI) were the risk factors of hypertension. Compared with non-drinkers, men who drank alcohol 20~29.9 g/day and over 30 g/day had adjusted relative risk for hypertension of 4.05 (95% confidence interval (CI) 1.09~15.08) and 1.37 (0.61~3.11), respectively. Family history of hypertension increased OR 5.35 times. Compared with men having BMI of less than 23 kg/ m2, the adjusted OR for men with BMI of 23~24.9 kg/m2 and over 25 kg/m2 were 2.39 (1.15~4.97) and 2.05 (0.96~4.39), respectively. For women, BMI was a risk factor of hypertension. Compared with women having BMI of less than 23 kg/m2, OR for women with BMI of 23~24.9 kg/m2 and over 25 kg/m2 were 3.51 (1.13~10.89) and 2.93 (1.28~6.72), respectively. CONCLUSION: Our study proved that obesity (men and women), alcohol intake (men), and family history of hypertension (men) were risk factors of hypertension in Korean adults.