Because of the importance of left ventricular (LV) hypertrophy (LVH) as a strong independent risk factor for adverse cardiovascular events, clinical trials of the treatment of hypertension have recently focused on the efficacy of antihypertensive agents to decrease LV mass. Although a decrease in LV mass appears in general to correlate with reduction of blood pressure, considerable variation is found. Clinical trials have found, for example, that decreases in LV mass tend to correlate with duration of treatment, class of antihypertensive agent and initial LV mass. Although there has been concern about possible adverse effects on LV function if antihypertensive agents are stopped abruptly after regression of LVH and blood pressure increases to previous levels, no evidence has been found for decreased LV function after 1 month. Regression of LVH has been found to produce such beneficial effects as a decrease in dysrhythmias and normalization of diastolic function. Most importantly, recent clinical trials have been designed to assess the independent effects of decreased LV mass on cardiovascular events. Preliminary studies suggest a decrease in cardiovascular morbidity.