Left-ventricular hypertrophy is the main cardiac consequence of systemic hypertension. Since it is an established, independent cardiovascular risk factor, its recognition is important. As the sensitivity of electrocardiography in this field is considered insufficient, echocardiography is the most widely used method for the determination of left-ventricular mass. In spite of its well-known limitations, we recommend applying the Penn convention using M-mode echo. In current practice we suggest including echocardiography in the diagnostic work-up of a hypertensive patient, provided that at least one additional cardiological argument is present-such as the suspicion of a structural or functional anomaly-since it generates not only left-ventricular mass but also a wealth of other information, particularly about the valvular as well as the systolic and diastolic left-ventricular function.