Thirty‐four cases of generalized amyloidosis were studied by the Congo red‐fluorescent method. In the majority of cases (32 cases) amyloid deposition was found more or less in the lung. The initial deposition in the alveolar wall was observed to start along fibrous structures of the alveolar wall, such as basement membrane, and also from smooth muscle of the alveolar wall, of interalveolar septa, and from small nodular mass appearing beneath the endothelium. Amyloid was deposited variably in the alveolar wall, and it was particularly marked in the subpleural and hilar regions, around the fibrosed lesions, especially on the atelectatic side. In a few cases marked or slight deposition was found in medium‐sized and small blood vessels. The pattern of deposition in such cases was, together with their X‐ray findings, designated as the vascular type. In the other type deposition was found in the alveolar wall and partly in the vascular wall and called as the diffuse type. In this type, with the increase of deposition, X‐ray shadows suggestive of pulmonary fibrosis may appear, and with still more marked deposition, symptoms of alveolar capillary block