ABSTRACT: Very little information is known about patients with chronic obstructive pulmonary disease who travel to high altitude for work or pleasure. Even less is known about the outcomes at high altitude for patients with severe bullous lung disease. We present the case of a 54-yr-old man with vanishing lung syndrome, an idiopathic form of severe bullous emphysema, who has made repeated trips to altitudes as high as 3400 m, where he has engaged in physical activity, such as downhill skiing. We consider the issues of adequacy of oxygenation and the risks of barotrauma in patients with obstructive lung disease traveling to high altitude, and we also consider factors, such as improved air-flow limitation, maintenance of adequate ventilation-perfusion matching, and underlying physical fitness, which may affect our patient's ability to tolerate physical activity in this environment. The case demonstrates that the presence of severe lung disease does not necessarily preclude travel to and moderate activity at high altitude. Such travel may, in fact, be safe as long as the patient has undergone appropriate pretravel evaluation, and we provide recommendations regarding such evaluation in patients with chronic obstructive pulmonary disease.