Chronic thromboembolic cor pulmonale is a serious condition and its frequency seems to be on the increase. The authors report their personal experience of 100 cases and review the literature to describe the natural history, diagnostic strategy and therapeutic indications of this condition. The mechanisms of this aberrant evolution of acute pulmonary embolism are unknown. They key symptom is effort dyspnea without a ventilatory deficit. The most useful diagnostic investigations are Doppler echocardiography and perfusion pulmonary scintigraphy. The diagnosis is confirmed by pulmonary angiography which, with the aid of a thoracic CT scan or endovascular techniques (ultrasonography or angioscopy), allow assessment of the feasibility of thromboendarteriectomy. Medical treatment is based on long-term anticoagulation, in some cases of lower limb thrombosis associated with interruption of the inferior vena cava. Two possible curative surgical techniques are available in selected patients; thromboendarteriectomy and pulmonary transplantation, the relative indications of which are listed. Of all the causes of pulmonary hypertension, chronic thromboembolic cor pulmonary should be systematically looked for because curative surgical treatment is possible in some cases.