The validity of angiocardiographic measurements in assessing the severity of pulmonic valve stenosis was determined. The pulmonic valve orifice area was measured in the lateral projection on cineangiocardiographic films in 24 patients with valvar pulmonic stenosis. The valve orifice area was also obtained in the same patients by the Gorlin and Bache formulae. The right ventricular output value required for insertion in these formulae was obtained by angiocardiographic right ventricular volume measurement and by the Fick method. The correlation between the directly measured valve orifice area and the area calculated using the Fick principle and the Bache formula was 0.80. The substitution of angiocardiographically measured right ventricular stroke volume for the Fick value gave a correlation of 0.82. The results support validity of employing direct angiocardiographic measurements of pulmonic valve orifice area and angiocardiographic right ventricular volume measurements for quantitative assessment of the severity of pulmonic valve stenosis. The angiocardiographic methods thus represent an alternative to the Fick technique which can be used in conditions where the Fick method cannot be expected to give valid results.