The echocardiographic findings in a total of 123 cases of essential hypertension were studied and compared with those of healthy subjects. Electrocardiographic patterns of essential hypertension were classified into 4 groups according to the Hypertension Criteria of the Departments of Internal Medicine, University of Tokyo. The group with normal electrocardiographic findings showed reduced diastolic E to F slope (DDR), decreased total amplitude (CE) and increased A/E ratio of the anterior mitral leaflet and enlarged left atrial dimension (LAD), and thickened interventricular septum in comparison with those of the healthy subjects. The differences were staistically significant. In essential hypertension, asymmetric septal hypertrophy (ASH) may be present, because the thickness of the interventricular septum was significantly increased, whereas the left ventricular wall thickness was only slightly increased. Left ventricular dimension was enlarged in advanced essential hypertension. It correlated well with decreased ejection fraction (EF), decreased mVcf and increased D/C ratio.