The authors report the results of a study on patients with chronic cor pulmonale hospitalized in the Departement of Cardiology (Dakar), from 1990 to 1998. The hospital prevalence is 0.9% with a male predominance (73.5%). The clinical signs were dominated by dyspnea and cough. The right heart failure is noted in 85.29% of cases. As far as the biological factor is concerned, it exists an polycythemia about 75% of cases, hypoxia (88.8%), hypercapnia (55.5%) and a respiratory acidoses (55.5%). The spirometry showed in 66% of cases, a mixed syndrom with obstructive predominance. The echocardiography showed in all cases right heart dilatation with pulmonary hypertension. The etiological factors are dominated by tobacco (21 cases). The hospital evolution has been favorable in 19 cases underoxygentherapy, lowdosediuretic, expectorant, bronchodilatators and salt restriction. However, 14 patients have died.