ACE inhibitiors have been recently used to treat the chronic congestive heart failure after the use of the antihypertensive agents.The enalapril was added to the chronic congestive heart failure patients unresponded to diuretics and digoxin. The echocardiography, serum chemical examinations, ECG, chest X-ray and clinical manifestations were done to the 47 patients with chronic severe congestive heart failure unresponded to diuretics and digoxin before and 2 months after the addition of enalapril between Feb. 1991 and Nov. 1991 in Dong-A Univerity Hospital. The results were followed : 1) The dyspnea, the hepatomegaly, the engorged jugular vein, cough, edema, palpitation, chest discomfort, and the tachycardia were improved 2 months after the treatment of enalapril. 2) The cardiomegaly and lung edema on the chest PA, and the elevated GOT, GPT and serum creatinine were improved 2 months after the treatment of enalapril. 3) Left ventricular end systolic dimension, fractional shortening, left ventricular end diastolic volume, and ejection time on the ECHO were significantly increased after 2 months of the treatment of enalapril. ACE inhibitor, enalapril revealed the effectiveness of the treatment to the patients with the severe congestive heart failure, and we should try to study the mortality rates to decrease compared with the control groups without the treatment of enalapril.