Background:Chronic dilated cardiomyopathy (DCM) usually progress to refractory heart failure and present a high mortality rate. But in patients with recent-onset DCM, there is about 50% chance of recovery in left ventricular (LV) systolic function. And in patients with chronic idiopathic DCM, there are reported of spontaneous improvement or stabilization up to 25%. In this study, we aimed to identify of reversal of systolic function and predictable factors. Method:Retrospectively, the patients(n=89, female=30) who admitted due to heart failure from October,2000 to October,2008, were enrolled in this study. The mean clinical follow-up duration was 33.8짹24.0 months. Ischemic cardiomyopathy was ruled out by coronary angiography. The idiopathic DCM was defined by Echocardiographic finding and by clinically (no known reversible transient cardiomyopathy). Echocardiographically, LVEDD over ���55mm & LVEF ���40% were included. Reversal of systolic LV dysfunction was defined by improvement of follow-up LVEF over 45%. Primary outcome was a reversal rate of systolic LV dysfunction. And secondary outcome was detect parameters for reversal of LV systolic function. Result: The mean age was 61.6 짹 15.2 years. Hypertension, diabetes, dyslipidemia, current smoking were accompanied by 35(39.3%), 21(23.6%), 31(34.8%), 32(36%) patients. Angiotension converting enzyme inhibitor or receptor blocker were used in all patients, Beta-receptor antagonist, diuretics, statin were used in each 76(85.4%), 72(80.9%), 19(21.3%) patients. The reversal of systolic LV function was achieved in 28 (33.7%) patients at follow-up echocardiography. Echocardiographically LVEDD, LVESD, LAVI, were decreased and LVEF, relative wall thickness were increased in statistically at follow-up. In comparing parameters between reversal group from non-reversal group, baseline SBP and DBP were higher in reversal group but other clinical parameters were not. The reversal group had smaller initial LVEDD, LAVI and higher relative wall thickness, deceleration time of mitral filling flow. In predicting follow-up LVEF, SBP and LVEDD were dependent factors in linear regression (LVEF = 34.864 + 0.273xSBP (mmHg) – 0.552x LVEDD(mm)) R2 = 0.354, Durbin-Watson (2.115), F=13.694, p=0.000. In overall, patients had relatively a good survival rate (92.7%). Conclusion : In idiopathic DCM patients, reversal of systolic LV dysfunction could be obtained by medical therapy alone. The predictors for follow-up of LV function (LVEF) were systolic blood pressure and LV end diastolic dimension. So we can delay or prevent of invasive treatment, early heart transplantation or LV volume reduction surgery by medical treatment only.