A case of malignant rheumatoid arthritis with renal failure seen in a 55-year-old housewife is reported. Rehumatoid arthritis has been present since 38-year of age. On Feburary 28, 1975, she was admitted to our hospital with a history of flea-uo arthralgia, high fever and malnutrition. Two years before admission, she suffered from Raynaud's phenomenon. Examination showed her to be cachectic, and facial and leg edema was noted. Examinations revealed leukocytosis with neutophilia, increased ESR, CRP +6, high titer of RA factor, hypergammaglobulinemia, hypoalbuminemia, renal and liver dysfunction and iron deficiency anemia. By the medication, she became well and had little, if any, complaints. She was discharged on June 3, 1975. Two months later, she was readmitted because of severe arthralgia with subcutaneous nodules, high fever and facial and leg edema. During this hospitalization, fluctuated hypertension (208/106-108/66 mmHg), proteinuria, oliguria and azotemia were detected. She succumbled to rapidly progressive renal failure and subarachnoidal hemorrhage on December 10, 1975. At postmortem examination, vasculitis of the small arteries and arterioles were found in systemic organs such as kindney, lung, heart and stomach. Especially the kindney had a fleabitten appearance as a result of ,multiple petechiae. On microscopic examination, some glomeruli appeared necrotic, and the interstitium was infiltrated by lymphocytes.