A simple method of assessing left ventricular function in stabilized chronic respiratory failure (CRF) is proposed. 21 patients with CRF were ranked according to the prediction of left ventricular function derived from eight elementary clinical criteria including standard chest X-ray and conventional basal electrocardiography. Equilibrium radionuclide angiocardiography was performed at rest (rERNA) for the evaluation of left ventricular systolic function (ejection fraction, LVEF; peak ejection rate) and diastolic function (peak filling rate). Right ventricular ejection fraction (RVEF) was also measured. The clinical evaluation of the left ventricular function showed a high correlation with rERNA data (p < 0.01 by Spearman’s rank test). No correlation was found between rERNA parameters and PaCo<sub>2</sub>and between RVEF and LVEF. The clinical criteria proposed can thus predict left ventricular function in stabilized CRF with a high degree of confidence.