We estimated right ventricular volume and ejection by two-dimensional echocardiography (2DE) and compared the measurements with those obtained by right ventricular cineangiography (ANGIO) in 20 children whose ages ranged from 1 month to 10 years and who had a variety of congenital defects. The two echocardiographic planes used for calculating volume were the apical four-chamber (A4C) and parasternal short-axis (SA) planes. End diastolic volume (EDV) and end systolic volume (ESV) were calculated from these planes by single-plane area-length methods. The EDV and ESV were uniformly underestimated, but the estimate of ejection fraction (EF) was satisfactory. For EF, r = 0.83 from the apical four-chamber view and r = 0.78 from the short-axis view. The axes of the two echocardiographic planes passed through different segments of the right ventricle (RV) and we found that the value given by adding the volumes obtained from the two single-plane segments correlated quite well with the value obtained by angiography: for EDV, 2DE = 0.62 ANGIO + 7.0, r = 0.81, standard error of the estimate (s.e.e.) = 15.4 ml; for ESV, 2DE = 0.82 ANGIO + 1.4, r = 0.85, s.e.e. = 6.5 ml; and for EF, 2DE = 0.66 ANGIO + 17.8, r = 0.82, s.e.e. = 7.4 ml. Two-dimensional echocardiography can be used to evaluate right ventricular EF derived from volume measurements or from each of the echocardiographic planes of which, in our series, the apical four-chamber EF provided the better correlation.