Abstract: AIM: To investigate the effect of cardiac resynchronization therapy (CRT) on dilated cardiomyopathy (DCM). METHODS: Thirteen patients with DCM were implanted with synchronous biventricular pacemakers. All patients had NYHA class III to IV heart failure with ejection fraction (EF) (27.4±9.7)%, left ventricular end-diastolic diameter (LVEDD) (72.8±9.6) mm and QRS duration of (137.8±30.4) msec. Serial assessment was performed before and after pacing. RESULTS: After a follow-up period of 3-38 months, there were significant improvements of NYHA class of heart function from (3.4±0.5) to (1.5±0.9). EF increased from (27.4±9.7)% to (43.5±18.5)% (P<0.05) and the LVEDD decreased from (72.8±9.6) mm to (65.5±11.6) mm (P<0.05). CONCLUSION: For patients with NYHA class III to IV heart failure and ventricular conduction delay, cardiac resynchronization therapy can reverse left ventricular remodeling and improve heart function.