Two-dimensional guided M-mode echocardiography was used to estimate left ventricular mass and left ventricular performance in 140 untreated hypertensive patients, 38 (27%) of whom had left ventricular hypertrophy. Left ventricular contractility as reflected by ratio of end-systolic wall stress to end-systolic volume index and normalised early left ventricular peak filling rate were decreased in the patients with left ventricular hypertrophy compared with those without hypertrophy and correlated inversely with the left ventricular mass (r = -0.44; P < 0.0001 and r = -0.31; P = 0.0004, respectively). Positive correlations were found between the peak filling rate and either the ejection fraction or the contractility index (r = 0.44; P < 0.0001 and r = 0.24; P = 0.004, respectively). Left ventricular mass also correlated with mean arterial pressure in the whole study population (r = 0.43; P < 0.0001). The data suggest that with the development of left ventricular hypertrophy both contractility and filling of the left ventricle become progressively impaired in hypertensive patients. The decline in cardiac function with progressive left ventricular hypertrophy may represent a pathophysiological correlate of the epidemiological observation identifying left ventricular hypertrophy as one of the most powerful risk factors for future cardiovascular morbidity and mortality. The present study shows that with development of left ventricular hypertrophy in essential hypertension both contractility and filling of the left ventricle become progressively impaired.