The authors describe two cases suffering from Caplan s syndrome, i.e. a combination of pneumo- coniosis and rheumatoid arthritis, in miners of deep coal mines in southern Moravia. The finding on the lungs preceded the manifestation of articular symptoms.The disease progressed even after the risk of fibrogenic dust was eliminated. In both patients occupational diseases were involved.

        Key words: Caplan s syndrome - Pneumoconiosis - Rheumatoid arthritis - Occupational diseases.