Left ventricular hypertrophy (LVH), an increase in the muscle mass of the left ventricle, has been identified as a powerful risk factor for future cardiovascular morbidity and mortality. The risk of acute myocardial infarction, congestive heart failure, sudden death, and other cardiovascular events increases six- to eightfold with the presence of LVH. The increase in myocardial mass lowers coronary reserve and enhances cardiac oxygen requirements, gives rise to ventricular ectopy, and impairs left ventricular filling and contractility. Hypertension, obesity, advanced age, valvular heart disease, and other disorders that cause an increase in the hemodynamic burden can lead to LVH. Left ventricular hypertrophy and its sequelae can be reduced by specific antihypertensive therapy but, despite these promising findings, future epidemiological studies are necessary to document the clinical benefits of a reduction of LVH.