We report a case of renal cell carcinoma with pulmonary metastases treated with recombinant alpha interferon and subsequently presenting as congestive heart failure due to a dilated cardiomyopathy. A 66-year-old man presented himself to the department of internal medicine at our hospital with a complaint of persistent cough with sputum on August 27, 1988. Ultrasonogram, computed tomography and angiography showed a right renal cell carcinoma and chest x-ray films disclosed bilateral multiple nodular shadows, probably representing metastases of the renal tumor. After being transferred to our department, the patient underwent the ligation of the right renal artery and vein and the postoperative treatment with recombinant alpha interferon, achieving a complete response for pulmonary metastases and a partial response for the primary region. On February 14, 1990 the patient was admitted to our hospital with a complaint of dyspnea to be diagnosed as congestive heart failure due to dilated cardiomyopathy. The interferon therapy was suspected to have caused the heart disease, and four months after discontinuation of interferon therapy the heart failure symptoms had improved, but hypokinesis of the cardiac wall still persisted. To our knowledge, this may be the first case of alpha interferon-related cardiomyopathy in Japan.