Autosomal dominant polycystic kidney disease is a systemic disorder with cystic manifestations in the kidneys, liver, pancreas, seminal vesicles, and meninges; its noncystic manifestations affect mostly the vascular, cardiac, and connective tissues. Cardiovascular abnormalities, including mitral and aortic valvular prolapse and regurgitation and annuloaortic ectasia, have been considered important extrarenal manifestations of autosomal dominant polycystic kidney disease. But there were no reports with dilated cardiomyopathy in patients with polycystic kidney disease yet. We have experienced a case of dilated cardiomyopathy that is associated by autosomal dominant polycystic kidney disease in 40 year old male patient. Abdominal ultrasonography revealed variable sizes of multiple cysts in both kidneys and echocardiography showed the marked dilatation of left ventricle and severely depressed left ventricular systolic function (ejection fraction=19%). He was treated with diuretics intravenously and orally. Then dyspnea and abdominal distension was improved. This is the first case of dilated cardiomyopathy with autosomal dominant polycystic disease in Korea.