Neurofibromatosis has been known to involve blood vessels throughout the body. Pulmonary involvement with interstitial fibrosing alveolitis has been described but no case of pulmonary vascular involvement has been reported to date. A 51 year old patient with cutaneous neurofibromatosis is described who presented with severe pulmonary hypertension and radiographic, scintigraphic, and angiographic evidence of chronic thromboembolic pulmonary hypertension. Severe intimal fibrosis consistent with vascular involvement with neurofibromatosis was found on endarterectomy with no evidence of pulmonary thromboembolism. Neurofibromatosis of pulmonary arteries should be considered as a possible cause of pulmonary hypertension.