Collagen tissue diseases are multisystem and heterogeneous group disease mediated inflammatory disorders. The pulmonary manifestations is more common and all elements of the lung are involved. However, symptoms of the respiratory system may be masked by exercise limitation due to involvement of the musculoskeletal system. The involvement may be subclinical or determined fulminant and life-threatening dimension. In this review, the pulmonary involvement of the more common collagen tissue diseases are reviewed.