BACKGROUND Carotid atherosclerosis is a risk factor for cardiovascular mortality and may represent hypertension-related target organ damage. Cardiorespiratory fitness is inversely associated with cardiovascular mortality in hypertensive men. We tested the hypothesis that higher levels of cardiorespiratory fitness are inversely associated with the prevalence of carotid atherosclerosis in a cross-sectional study of 2532 (53.2 +/- 8.5 years old) hypertensive men. METHODS Men with hypertension (defined as systolic over diastolic blood pressure of > or = 140/90 mm Hg or self-reported use of antihypertensive medication) underwent maximal exercise treadmill testing with expired gas analysis. Carotid atherosclerosis was defined as stenosis of > 25% and/or intima-media thickness of > 1.2 mm using B-mode ultrasonography. RESULTS The overall prevalence of carotid atherosclerosis was 13.4%. The prevalence of carotid atherosclerosis was inversely associated with cardiorespiratory fitness category (low 22.5%, moderate 10.9%, and high 8.7%; P < .001 for trend). After adjusting for established risk factors, high and moderate fitness were associated with lower odds ratios for having carotid atherosclerosis, 0.63 (95% CI 0.47-0.85) and 0.62 (95% CI 0.41-0.92), respectively, compared with low fitness. Each metabolic equivalent increment higher peak oxygen uptake was associated with 11% (odds ratio 0.89, 95% CI 0.82-0.97) lower prevalence of carotid atherosclerosis. CONCLUSIONS These results suggest that higher levels of cardiorespiratory fitness are inversely associated with the prevalence of carotid atherosclerosis in hypertensive men.