Pulmonary alveolar proteinosis is a very rare disease, first described by Rosen in 1958. It is characterized by the accumulation of lipoproteins in the pulmonary alveoli. Clinical and radiologic presentations are typical for the interstitial lung disease. Only few cases of this disease have been described in the Polish literature. A patient with disseminated lesions to the lungs is presented. A diagnosis was possible after an analysis of BAL fluid and histological examination of the lung tissue collected by the transbronchial biopsy.