Abstract-Recently the Joint National Committee on the Prevention, Detection, Evaluation, and Treatment of High Blood Pressure introduced the term "prehypertension" for systolic blood pressure levels of 120 to 139 mm Hg and diastolic BP levels of 80 to 89 mm Hg. Little is known about the prevalence of this entity and the cardiovascular risk factors associated with it. We aimed to determine the prevalence of prehypertension and the cardiovascular risk factors associated with it in a large population-based sample of young Israeli adults. We studied 36 424 Israel Defense Forces employees during the years 1991 to 1999. Subjects completed a detailed questionnaire and underwent physical examination, and blood samples were drawn after a 14-hour fast. Prehypertension was defined as a systolic blood pressure of 120 to 139 mm Hg, and/or a diastolic blood pressure of 80 to 89 mm Hg. We calculated the age-and sex-specific prevalence of prehypertension and other cardiovascular risk factors associated with this condition. Prehypertension was observed among 50.6% of men and 35.9% of women. The prehypertensive group had higher levels of blood glucose, total cholesterol, low-density lipoprotein cholesterol, and triglycerides, higher body mass index, and lower levels of high-density lipoprotein cholesterol than did the normotensive group. Multivariate logistic regression analysis showed that body mass index was the strongest predictor of prehypertension among both males and females (odds ratio, 1.100; 95% CI, 1.078 to 1.122 and odds ratio, 1.152; 95% CI, 1.097 to 1.21, respectively, for every 1 kg/m 2 increase). Our findings support the recommendation of lifestyle modification for prehypertensive patients. Further prospective studies are required to determine the role of pharmacotherapy in prehypertension. Key Words: cardiovascular diseases Ⅲ young adults Ⅲ hypertension, borderline H ypertension is likely the most common disease on Earth. 1 It is associated with an increased risk of morbidity and mortality from cardiovascular disease (CVD) and represents the single greatest preventable cause of death in humans. The standard definition of hypertension as blood pressure (BP) Ն140/90 mm Hg is based on the observation that the risk of CVD increases sharply above this level. However, recent data have shown that an increased risk of CVD is present in persons with BP levels as low as 115/ 70 mm Hg and that this risk increases steadily with rising BP. 2 The incremental association between BP and CVD risk has been reflected recently in the Seventh Report of the Joint National Committee on the Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC7). 3 In its report, the JNC7 introduced a new BP category, "prehypertension," defined as a systolic BP (SBP) of 120 to 139 mm Hg and/or a diastolic BP (DBP) of 80 to 89 mm Hg. Since the publication of the JNC7 report, several studies have assessed the prevalence and significance of prehypertension. Still, the importance of this entity in regard to global CVD risk and the pref...