The level of left ventricular (LV) mass as measured by echocardiography or other techniques in hypertensive patients reflects the integrated effects of the level of arterial pressure, the concomitant volume load imposed on the heart, and of alterations in arterial waveform morphology as well as of body size and non-hemodynamic variables. The LV may respond to these stimuli by concentric or eccentric hypertrophy or by the recently-described pattern of concentric remodeling, in which LV mass is normal but relative wall thickness is increased. The are strong parallelisms between increases in cardiac and systemic arterial wall thicknesses, and patients with discrete atheromas detectable by carotid ultrasound have elevated LV masses. Patients with eccentric and concentric LV hypertrophy have two to four-fold increases in the incidence of cardiovascular morbid events compared to hypertensive patients with normal LV geometry, and the change in LV mass during treatment has been associated with the risk of subsequent morbidity in initial studies. In contrast to the strong predictive power of LV geometric assessment, use of indirect measures of target organ status in the WHO system for classification of the severity of hypertension does not improve on the prediction of prognosis that can be obtained by consideration of the level of arterial pressure. Current evidence suggests that evaluation of LV geometry may contribute to improved clinical decision-making in situations where more precise stratification of risk would clarify whether or not to institute treatment, or whether it should be with drugs or non-pharmacologic measures.