Background Myocardial infarction (MI) is one of the major etiologies of chronic heart failure (CHF) in Japan. Methods and Results The prognoses of CHF patients after MI (n=283) were investigated by comparing them with those of CHF patients with nonischemic cardiomyopathy (NICM, n=310) from the CHF registry (CHART; n=1,154). The Kaplan-Meier (KM) analyses revealed that the 3-year all-cause mortality was significantly higher in the MI cohort compared with the NICM cohort (29.0% vs 12.4%, p<0.0005). Age/gender/treatment-adjusted KM analysis revealed significant differences only in the cohorts with preserved left ventricular ejection fraction (LVEF), defined as LVEF >45%, or in less symptomatic patients (New York Heart Association I or II). Multivariate Cox regression analysis showed that β-blocker (BB) was associated with a significant reduction in mortality from cardiac causes, and either angiotensin-converting enzyme inhibitor or angiotensin receptor blocker (ACEI/ARB) was significantly related to the improvement of survival in the MI cohort (adjusted hazard ratio: 0.222 and 0.497, p<0.05), even though these medicines were used significantly less often in the MI cohort. Conclusions Underlying MI has a significant impact on the survival of Japanese CHF patients, especially those with preserved LVEF or with fewer symptoms. The appropriate expansion of ACEI/ARB or BB therapy might be necessary to improve their survival. (Circ J 2005; 69: 143 - 149)