Fibronectin is a paradigm adhesive protein which has been implicated in the regulation of several cellular processes and cell-cell interactions. Large amounts of fibronectin have been detected in atherosclerotic plaques, while hypertension in animal models has been shown to rapidly increase fibronectin expression in arterial walls. The aim of the present study was to determine the levels of plasma fibronectin (FN) in 133 patients with ischemic heart disease and in 36 normal controls, and to investigate the possible association with blood pressure. Plasma FN levels in patients with ischemic heart disease were found to be significantly elevated (mean±S.D.; 46.5±14.2 mg/dl) compared with the control group (38.0±14.2 mg/dl) (P=0.002). Plasma FN concentrations were significantly different between the hypertensive group (52.9±14.5 mg/dl) and the normal blood pressure group (41.4±11.8 mg/dl) among the patients with ischemic heart disease (P<0.001). Plasma FN concentration was positively correlated with total cholesterol, triglyceride, systolic blood pressure and body mass index. In conclusion, the plasma fibronectin level may have pathogenetic implications in association with lipid components and blood pressure in patients with ischemic heart disease.