Chronic thromboembolic pulmonary hypertension (CTEPH) should be suspected in patients presenting persistent dyspnea three months after a pulmonary embolism or in patients presenting with acute pulmonary embolism and suggestive images on the CT-scan. For these patients, a specific diagnostic work-up should be performed. First step consists of the ventilation/perfusion (V/Q) scan which is a good screening test due to its high sensitivity and high negative predictive value. Pulmonary angiography remains the gold standard approach for the confirmation of the diagnosis and pre-surgical evaluation of CTEPH. New emerging technologies such as Dual-Energy Computed Tomography angiography (DECT) and Computed Tomography angiography (CTA) are developing and broadly available. These non invasive methods provide diagnostic information similar to conventional pulmonary angiography and surgical operability information. They are to be considered as an alternative in the diagnostic approach of patients with CTEPH as presented in the ESC/ERS guidelines. Haemodynamic measurement whiles exercising during right heart catheterization may improve diagnostic sensitivity of CTEPH and could therefore be used as a diagnostic test in patient with normal haemodynamic at rest.