A 58-year-old woman was hospitalized in March, 1991, with slight breathlessness on exertion. Laboratory investigations revealed M-protein (IgG lambda type, 7,575mg/dl) in serum, and Bence-Jones proteinuria. Osteolytic bone lesions were noted roentgeno-logically. Bone marrow aspiration showed the presence of 19% of atypical plasma cells, and the case was diagnosed as multiple myeloma. The chest X-ray film showed bilateral diffuse micronodules, which were found by a transbronchial lung biopsy to be diffuse parenchymal amyloid deposits. The patient was treated with melphalan, prednisolone and interferon-alpha for 6 courses. Clinical symptoms improved but no decrease of the level of M-protein was observed. The patient is still alive without changes of pulmonary shadows on X-ray films for the past 2 years.