Early detection of diastolic dysfunction in chronic obstructive lung disease (COLD) patients could have great prognostic value. Echocardiography has been shown to be a useful technique in studying left ventricular diastolic function. A noninvasive method of studying right ventricular diastolic function has not yet been reported. Pulsed Doppler echocardiography was used to assess right ventricular diastolic function in three groups of subjects: Group I: 35 COLD patients with pulmonary hypertension; Group II: 32 COLD patients without pulmonary hypertension; and Group III: 18 control subjects. Ratios between peak atrial filling velocity (A) and peak early filling velocity (E) (A/E), deceleration half times of the right ventricular rapid filling wave (DHT), and the interval between pulmonary valve closure and tricuspid valve opening (isovolumic relaxation times) (Pc-To) were significantly different in Group I in comparison to Groups II and III. Sensitivity of A/E ratio and Pc-To were 82 and 77%, respectively, and specificity 90 and 72%, respectively; positive predictive values were 90 and 75%, respectively, and negative predictive value 82 and 74% respectively. The multiple correlation coefficient between A/E, acceleration time (ACT), DHT, Pc-To and mean pulmonary artery pressure was 0.75 for Groups I and II together. In conclusion 2D echo-Doppler proved to be useful in evaluating right ventricular diastolic function in all hypertensive COLD patients, revealing a high correlation between diastolic parameters and mean pulmonary artery pressure in both normotensive and hypertensive COLD patients.