Left ventricular hypertrophy (LVH), a common complication of hypertension, is an important risk factor for cardiovascular disease. Patients with LVH are at a markedly increased risk for many cardiovascular complications and death. This heightened risk can be mitigated in part by antihypertensive therapy-induced regression of LVH. The electrocardiogram (ECG) is a valuable modality in the identification, risk stratification, and longitudinal follow-up of patients with hypertension and LVH. This article details the prognostic significance of ECG LVH and the benefits associated with treatment-induced LVH regression.