The case od 22-years old woman with pulmonary microlithiasis is described. The diagnosis was confirmed by histopathological examination of lung tissue. In electron microscopy lung fibrosis was seen. High resolution computed tomography (HRCT) and pulmonary function tests (lung compliance, diffusion capacity, exercise test) were done. The role of bronchoalveolar lavage (BAL) and lung scintigraphy with technetium in the diagnostic procedure of this disease is discussed.