In a retrospective study of 162 cases of rheumatoid arthritis we found that 24 patients (14.8%) had presented with microscopic haematuria with or without proteinuria. Renal biopsy had been performed in 15 of these 24 patients. Apart from the classical lesions of extramembranous glomerulonephritis, amyloidosis and interstitial nephritis, 60% of histological results showed lesions of mesangial glomerulonephritis. These lesions seemed to be independent of maintenance treatments, but they might have been facilitated by the chronic inflammation kept going by the rheumatoid disease itself.