Background: Temporal changes in Doppler indices of diastolic function during exercise remain unclear in patients with dilated cardiomyopathy (DCM). Methods: Supine bicycle exercise at low-grade (25W for 4 minutes) was done in 17 DCM patients (56짹11 years-old; LVEF 31짹 8%) and 33 normal controls (40짹11 years, LVEF 67짹6%). Echo-Doppler transmitral parameters (E, A, DT,IVRT) and mitral annular parameters (E���, A���) were measured at rest and exercise. % change of E during exercise (��E) was measured. Results: During exercise, E increased to 106짹26 from 63짹25 cm/s in DCM and to 107짹21 from 78짹15 cm/s in control. ��E was significantly higher in DCM than in control (85짹64% vs 39짹25%, p=0.001). E/E���(13.7짹6.4 in DCM, 5.8짹1.6 in control) did not change significantly during exercise in both groups because of concomitant increase of E���. While ��E in control was not correlated with resting E/E���(r=-0.25; p>0.05), significant negative correlation was detected in DCM (r= -0.60, p=0.011, figure A). Although ��E was higher in DCM than in control, DCM with > 15 of E/E��� (n=6) showed similar level of ��E to control (figure B). Conclusion: The change of early transmitral E velocity increased significantly in DCM than in normal. This might be explained that elevated filling pressure in DCM increased E velocity in early stage of exercise. However, progressive decrement of ��E over E/E���in DCM indicated that filling capacity might be restricted in patients with advanced diastolic function in spite of elevated filling pressure.