Systemic sclerosis (SSc) is an autoimmune disorder characterized by accumulation of collagen in affected organs, mainly the skin and the lungs, associated with abnormalities of the arterioles and capillaries. There are two types of pulmonary involvement, which influence long term prognosis: infiltration of the lungs and/or pulmonary artery hypertension. Full investigations into possible lung involvement must be performed systematically when SSc is diagnosed and during follow-up. The double pathophysiology sometimes makes diagnosis difficult but it must be made as early as possible in order to decide on the optimal treatment. The aim of this study was to evaluate the usual explorations and to propose biological markers to identify patients requiring more detailed lung investigations, in order to establish a diagnostic approach to treatment and follow-up patients with SSc.