Inflammation plays an important role in the development of atherosclerosis, but the specific stimuli governing cytokine release in atherogenesis are unknown. We examined the hypothesis that hypertension may increase the risk of atherosclerosis via proinflammatory effects. In a cross-sectional study involving 508 apparently healthy men, we studied the association between blood pressure and baseline plasma concentrations of 2 inflammatory markers, intercellular adhesion molecule-1 (sICAM-1) and interleukin-6 (IL-6). Increase in systolic blood pressure (SBP) (P=0.003), pulse pressure (PP) (P=0.019), and mean arterial pressure (P=0.014) was significantly associated with levels of sICAM-1. All of these measures of blood pressure, as well as diastolic blood pressure (DBP), were significantly associated with levels of IL-6 (all, P</=0.001). In multiple linear regression models controlled for age and other cardiac risk factors, SBP (7.6 ng/mL per 10 mm Hg, P=0.016) and PP (8.13 ng/mL per 10 mm Hg, P=0.038) were significantly associated with sICAM-1 levels, whereas SBP (0.11 pg/mL per 10 mm Hg, P<0.001), DBP (0.11 pg/mL per 10 mm Hg, P=0.008), PP (0.10 pg/mL per 10 mm Hg, P=0.009), and mean arterial pressure (0.15 pg/mL per 10 mm Hg, P<0.001) had similar strong relationships with log-transformed IL-6 levels. Therefore, in apparently healthy men, we observed significant graded relationships between blood pressure and levels of sICAM-1 as well as IL-6. These data suggest that increased blood pressure may be a stimulus for inflammation and that this is a possible mechanism underlying the well-established role of hypertension as a risk factor for atherosclerotic disease.