Background and objectives: Cardiac resynchronization therapy (CRT) improves hemodynamic function, heart failure symptoms, exercise capacity, partially reverses maladaptive remodeling, the NYHA classification system, and reduces morbidity and mortality. The aim of this study was to assess the number of Korean patients with heart failure who met the criteria for CRT, and combined CRT and defibrillation (CRT-D). Subjects and Methods: This was a retrospective review of 762 patients admitted with a diagnosis of heart failure to the Catholic medical center in Korea between January 2004 and May 2005. We examined their ECG and echocardiography, and classified each patient with the primary diseases of heart failure and NYHA classification. Results: The primary diseases of 762 patients with CHF included ischemic cardiomyopathy (232, 30.4 %), idiopathic dilated cardiomyopathy (215, 28.2 %), and cardiomyopathy from valve dysfunction, hypertension and other origin (315, 41.4 %). Among 447 patients with ischemic or idiopathic dilated cardiomyopathy, 50 patients (11.2 %) met the criteria for CRT indication based on both ACC/AHA/NASPE 2002 guidelines and ACC/AHA 2005 guideline update, and 37 patients (8.3 %) satisfied the criteria of ACC/AHA/NASPE 2002 guidelines. When patients with a class I indication for an ICD in ACC/AHA/NASPE 2002 guideline adapted in MIRACLE-ICD II trial were classified as eligible for ICD, 6.6% and 16.9%/13.6% of patients with CHF met the criteria for ICD and CRT-D indication respectively. When patients with a class I and a class IIa indication for an ICD in ACC/AHA/NASPE 2002 guideline adapted in MADIT II trial were classified as eligible for ICD, 17.0% and 30.3%/27.7% of patients with CHF met the criteria for ICD and CRT-D indication respectively. Conclusion: The primary diseases of heart failure were ischemic cardiomyopathy (30.4 %), idiopathic dilated cardiomyopathy (28.2 %), and cardiomyopathy from valve dysfunction, hypertension or unknown origin (41.4 %). We have demonstrated in Korean population that 11.2%/8.3% of patients presenting with heart failure might benefit from CRT and that 6.6~17.0% would benefit from ICD. Thus, 13.6~30.3% of patients with heart failure were candidates for CRT-D.