Cross sectional echocardiography can be used to determine left ventricular size and ejection fraction in children. We used two orthogonal planes from the apical four and two chamber planes to calculate the left ventricular volume in 20 children with a variety of congenital heart lesions and compared these volumes with those calculated using angiography. Better correlations were achieved at end diastole than at end systole. Comparisons between ejection fraction calculated by angiography and echocardiography showed the correlation was closer for two-dimensional than M-mode techniques. Studies using newer two-dimensional methods suggest that an even closer correlation for volume and ejection fraction can be achieved than those reported in our initial studies. Most studies which have determined right ventricular volume have used biplane methods combining short axis and four chamber images. We used single plane area-length methods from parasternal short axis and apical four chamber planes to calculate right ventricular volume in 20 children undergoing angiocardiography for a variety of congenital heart diseases. The single plane volume method underestimated the volume calculated from angiography uniformly so that a good estimate of the angiographic ejection fraction was obtained. Adding the volumes derived from each plane provided a closer approximation of the angiographic volumes and a good estimate of the ejection fraction. High resolution ultrasound equipment and computer assisted tracing devices have made accurate noninvasive assessment of volume and function accurate and practical.