Rheumatoid arthritis (RA) is a systemic disorder that primary involves joints, although renal disease has also been associated it is not common that rapidly progressive glomerulonephritis (RPGN) appears. We report the case of a patient with nodular and aggressive RA who had an acut renal failure secondary to ANCA positive RPGN due to a Microscopic polyangiitis who was not responsive to steroids and cyclophosphamide therapy.