The guidelines of the Joint National Committee 7 from the USA on hypertension have unified the normal and high-normal blood pressure categories into a single entity termed `prehypertension'. In contrast, The European Guidelines for the management of hypertension in 2007 considered `prehypertensive' to be divided into normal and high-normal blood pressure. These patients with high-normal blood pressure or prehypertension might progress to hypertension over time. Previous studies have shown that high-normal blood pressure is a risk factor for cardiovascular disease (CVD) in Western countries and Japan. The combination of high-normal blood pressure and other cardiovascular risk factors increases the risks of CVD. Recently, metabolic syndrome has also been shown to be a risk factor for CVD. In Japan, the association between metabolic syndrome and CVD was also found to be significant. The risks for CVD incidence were similar among participants who had the same number of components, regardless of the presence of abdominal obesity. In the Japanese guidelines for the management of hypertension published in 2009, patients are considered to be in a high-risk group if they have diabetes, chronic kidney disease, 3 or more risk factors, target organ damage or CVD, even if they have only high-normal blood pressure, and appropriate antihypertensive therapy should be initiated. (Circ J 2009; 73: 1381 - 1385)