Pulmonary hypertension and interstitial lung disease are the two main causes of death in systemic sclerosis. The hallmark of these complications is dyspnea on exertion. Assessment of dyspnea in systemic sclerosis is based on a questionnaire; 6-minute walk test and Borg index. After excluding anemia, a deceptive cause mainly due to digestive haemorrhage, echocardiography, pulmonary function tests and high resolution computed tomography of the chest are the first step to diagnosis. Peak velocity of tricuspid regurgitation as measured by echocardiography is the main parameter to evaluate the risk of pulmonary hypertension before performing a right heart catheterization. Diastolic left ventricle dysfunction is another frequently encountered cause of dyspnea in systemic sclerosis. Other less common causes are pericarditis, respiratory muscle involvement, lung cancer, pulmonary embolism.