The authors examined by two-dimensional echocardiography a group of 186 healthy children from birth to the age of 18 years. From the assembled records they measured the following: the inner diameter of the inferior vena cava, the diameter of the abdominal aorta, the area of the right and left atrium at the end of systole, the width of the ring of the tricuspid and mitral valve at the end of diastole, the area of the right and left ventricle at the end of systole and its circumference, the width of the annulus of the pulmonary artery, the diameter of the aortic arch, the diameter of the right and left branch of the pulmonary artery. The systolic function of the left ventricle and the curvature of the ventricular septum during systole was calculated from the assessed parameters of the left ventricle. By means of a computer the regression equations of the relation of assessed echocardiographic parameters and body weight and body surface were calculated as well as their mean values +/- 2 standard deviations for the given body weight and body surface which are considered normal for the child population.