Although it has been suggested that alcohol intake is related to hypertension, few long-term prospective studies have investigated this relationship. We therefore conducted a prospective study in male residents of a farming community in Japan to determine whether heavy drinking would predispose to the development of hypertension. A total of 325 normotensive (< 140/90 mm Hg) men were enrolled in 1977. Twelve years later, 93 (28.6%) subjects became hypertensive (defined as blood pressure > or = 140/90 mm Hg or use of antihypertensive medication). The probability of the development of hypertension in heavy drinkers predicted from a logistic regression equation was 44.6% (relative risk: 2.05 versus nondrinkers) after adjusting for age and body mass index (BMI). It was 36.2% (relative risk: 1.86 versus nondrinkers) after a further adjustment for systolic blood pressure at baseline. A high odds ratio of 2.39 for the development of hypertension with alcohol intake of < 46 g/day versus > or = 46 g/day at baseline was obtained even after adjustments for age, BMI, and confounding factors. We conclude that habitual heavy drinking of alcohol is a risk factor for the development of hypertension. This is the first report demonstrating a significant relationship between habitual alcohol intake and the development of hypertension in a long-term prospective study in Japan.