Chronic thromboembolic pulmonary hypertension (CTEPH) is a rare and potentially fatal disease which occasionally occurs as a complication of acute pulmonary embolism. The mechanisms leading to failure of thrombus resolution are not completely understood with only some risk factors identified. Vascular alterations are present in the large and small vessel compartment. Signs and symptoms of CTEPH are nonspecific, rendering diagnosis challenging. A VQ scan followed by computed tomography, magnetic resonance or conventional pulmonary angiography is mandatory to confirm diagnosis and assess operability by a multidisciplinary team. Pulmonary endarterectomy remains the treatment of choice in operable patients and results in significantly improved haemodynamics and functional capacity. In inoperable patients medical treatment is well defined, and mainly includes the recently introduced pharmacological substances with impact on haemodynamics and functional performance.