Increase in the relative risk of development of secondary malignancy in patients with rheumatoid arthritis (RA) have been demonstrated, possibly either due to underlying immunological disorders, or to cytotoxic drugs used for therapy. In addition, RA itself and drugs may cause numerous renal and pulmonary disorders. Here, we describe a 52-year-old-woman with a 15-year history ofRA who developed acute renal failure due to multiple myeloma. She also had severe pulmonary fibrosis as a complication of RA. Our findings suggest that renal involvement due to multiple myeloma should be kept in mind in differential diagnosis of renal dysfunction in patients with RA.