Relations of fibrinogen to preclinical target organ damage, such as left ventricular hypertrophy, systolic dysfunction, and increased arterial stiffness while accounting for traditional risk factors, are unknown in a population-based sample free of clinically overt coronary heart disease. Therefore, we studied clinical and echocardiographic characteristics of 2709 American Indians participating in the Strong Heart Study without symptomatic atherosclerosis. The study sample was divided into tertiles of fibrinogen (cut-points, 3.24 and 3.83 g/L). Mean age, body mass index, proportion of women, and prevalences of hypertension and diabetes increased from the first to third tertile of fibrinogen. After adjustment for covariates, systolic and pulse pressures did not significantly differ among tertiles of fibrinogen, whereas diastolic pressure was slightly lower in the third than in lower tertiles of fibrinogen. HDL cholesterol was lower and plasma creatinine and urinary albumin/creatinine ratio was higher in the third tertile of fibrinogen. Left ventricular mass index, pulse pressure/stroke index, an estimate of arterial stiffness, and cardiac index were higher and left ventricular systolic function and total peripheral resistance were lower in the third than in two lower tertiles of fibrinogen independent of major covariates. In multiple regression analyses, left ventricular mass and pulse pressure/stroke index were positively associated with, and stress-corrected midwall shortening negatively associated with fibrinogen, independent of major covariates. Participants with fibrinogen >3.83 g/L were more likely to have at least 1 preclinical cardiovascular abnormality such as left ventricular hypertrophy, elevated arterial stiffness, or systolic myocardial dysfunction independent of covariates including renal dysfunction (adjusted odds ratio, 1.38; P<0.001). Thus, in a population sample of adults without clinically overt coronary heart disease, elevated fibrinogen is an independent correlate of prognostically relevant cardiovascular target organ damage.