Right ventricular ejection fractions were determined by videodensitometric computer analysis of digital subtraction angiography in 50 patients with various cardiac diseases. Using intravenous injection of 35 ml sodium meglumin diatrizoate at a constant rate of 12 ml/min, serial right ventriculograms were obtained in the right anterior oblique projection. Right ventricular enddiastolic and end-systolic counts and ejection fractions were obtained by integrating densitometric counts within the, right ventricular region of interest, in addition to application of the conventional pyramidal method. The obtained right ventricular densitometric counts correlated closely (r=0.91) with the single-plane right ventricular volumes. The right ventricular ejection fraction determined by video-densitometry also exhibited satisfactory correlation (r=0.74) with that by single-plane ventriculography. Thus, videodensitometric analysis of digital subtraction right ventriculograms are an acceptable method for the determination of the right ventricular ejection fraction, and therefore videodensitometric analysis is recommended as a convenient method for clinical practice.