Two-dimensional echocardiography is superior to M-mode echocardiography for estimation of left ventricular mass when left ventricular shape is markedly abnormal. Left ventricular mass measurement by two-dimensional echocardiography depends on careful experimental calibration of the echocardiographic instrument using either a standard phantom or actual heart slices, and appropriate geometric algorithm, and short axis images to determine myocardial cross-sectional area. Several well-validated algorithms are available, of which the short-axis area-length technique is the simplest. In hypertensive heart disease, in which left ventricular shape is usually close to normal, two-dimensional echocardiography may offer a smaller standard error than M-mode, but this issue requires further evaluation. Further, it is uncertain whether the incremental accuracy of two-dimensional echocardiography in hypertensive heart disease would offset its increased cost and complexity relative to M-mode echocardiography.