The authors report on one case of pulmonary bilharziosis at Schistosoma mansoni observed in a West-Indian female showing an impairing of her general condition with fever and dyspnea. Diagnosis was brought out by a pulmonary biopsy, after thoracotomy. Treatment by praziquantel was remarkably efficient. Scarcity of symptomatic cases and paucity of pulmonary radiological pictures are opposite of the frequency of pathological lesions in this parenchyma. The authors discuss the physiopathology of pulmonary bilharziosis in both their invading phase and state phase, as well as their frequency. They come to the conclusion that both parasitological examination of stools and biopsy of mucous membrane of rectum are simple, reliable and harmless implements of diagnosis.