The present study describes the total intrinsic variability of both left ventricular wall thickness and left ventricular wall mass in a group of 11 normal volunteers with an echocardiographic follow-up of about 1 yr. Septal thickness, posterior wall thickness and left ventricular minor diameter were measured at end-diastole. From the parameters under investigation the left ventricular minor diameter showed the best reproducibility with a coefficient of variation of 4%. The coefficients of variation for septal thickness, posterior wall thickness and left ventricular wall mass by both the Penn and the ASE method were 10, 10, 15 and 13%, respectively. The left ventricular wall mass was better reproducible by the ASE method than by the Penn method.