Objective To assess the therapeutic effect of losartan on cardiac remodeling for patients with idiopathic dilated cardiomyopathy (IDCM). Methods From Jan.1997 to Dec.2002,UCG was performed in 56 patients with IDCM.They were divided into two groups.The first group of 30 patients were treated with losartan (50mg) plus ?-receptor blocker per day.The other group of 26 patients received standard conventional therapy,including cardiac,diuretic and potassium-spring.All patients were interviewed once a month for the following 6 months.The results of UCG were based on the examination taken by the end of 3 months and 6 months. Results In the first group,UCG improved significantly ( P 0.05). Conclusion Losartan may be effective to restrict the heart reconstruction and reduce the heart weigh and improve the heart function after 3-month therapy and may be more effective after 6 months of therapy.