We present here a case of severe haemoptysis occurring 2 times in a man having some anomaly of lung development, i.e. a right pulmonary artery agenesis. We ought to keep in mind these anomalies of lung development which are quite rare. Moreover in absence of pulmonary artery, the ipsilateral lung parenchyma is vascularized by systemic circulation and exposed to very high systemic pressure responsible for very severe haemoptysis requiring sometimes a pneumonectomy to be controlled. Finally we make a short review on etiology of lung haemoptysis.