The patient was a 63-year-old woman. She was admitted to our hospital with acute renal failure and multiple mononeuritis in 2002. She was diagnosed as microscopic polyangiitis based on positive for MPO-ANCA. Remission was induced by combination therapy with methylprednisolone pulse therapy and plasma exchange. Because condition of the disease was stable, prednisolone was discontinued from August 2006. Elevation of serum creatinine and microscopic hematuria was detected in November 2007. Fever and dyspnea occurred in January 24 2008. Elevation of CRP and serum creatinine was found, and infiltration in bilateral lung was noted on chest X-ray. She was admitted on the same day. After admission, she presented with hemosputum and exacerbation of dyspnea. Chest CT revealed diffuse consolidation and ground glass opacity, and MPO-ANCA converted to be positive. Diagnosis of diffuse alveolar hemorrhage and rapidly progressive glomerulonephritis with microscopic polyangiitis was made, and she was managed by artificial respirator and CHDF in ICU. Combination therapy with steroid pulse therapy and plasma exchange re-induced remission. Mizoribine was administrated as maintenance therapy with oral prednisolone.