It is well established that left ventricular hypertrophy is a strong and independent risk factor for cardiovascular morbidity and mortality. This study was designed to determine the prevalence and correlates of left ventricular hypertrophy (LVH) among a sample population of 2318 totally asymptomatic men aged 40-59. This sample is a subset of the participants in the ECCIS Project. Left ventricular mass was estimated by echocardiography. The following individual variables were employed in the multiple linear regression analyses: age, diastolic and systolic blood pressure at rest and at peak exercise, body mass index, body surface area, conditioning physical activity. Three indexes of left ventricular mass were used: left ventricular mass/height, left ventricular mass/body surface area and "adjusted left ventricular mass" derived from adjustment, using a regression model, of left ventricular mass by age, body mass index and body surface area. The sample was subdivided in 3 blood pressure classes; normotensive (n = 1605), borderline (n = 390) and hypertensive (n = 323). All the variables considered with the exception of diastolic blood pressure both at rest and peak exercise were significantly correlated with left ventricular mass. Upper normal limits for left ventricular mass indexed to height and body surface area and of adjusted left ventricular mass were 143 g/m, 129 g/m2, and 245 g respectively. The prevalences of left ventricular hypertrophy, as determined by the reference standard of left ventricular mass/height, left.ventricular mass/body surface area and adjusted left ventricular mass, ranged 2.7-3.2% in the normotensive group, 4.2-5.4% in the borderline group and 11.8-14.5% in the hypertensive group, and were lower using adjusted left ventricular mass index. The results of this study show that the prevalence of left ventricular hypertrophy using adjustment by age, body surface area and body mass index reduces variability of left ventricular mass associated with age and body size and may be useful for the correct identification of left ventricular hypertrophy and hypertensive heart disease.