We report 2 rare cases of non-Hodgkin's lymphoma accompanied by pulmonary involvement with diffuse ground-glass opacity. Histological examination of the lung revealed a diffuse large B-cell-type lymphoma within the bronchiolar wall and alveolar septum. Although this is a rare occurrence, diffuse large B-cell-type non-Hodgkin's lymphoma should be considered in the differential diagnosis of pulmonary diffuse ground-glass opacity in the chest CT scan.