An association of neurofibromatosis with diffuse interstitial lung disease is thought to exist, though there have been relatively few large studies of it. The pulmonary manifestations consist of diffuse interstitial fibrosis or formation of bullae, or a combination of both. Our experience with this disease process during a ten-year period shows slightly less than a 7% incidence of diffuse interstitial lung disease in our patients with neurofibromatosis. We include a case of neurofibromatosis and diffuse lung disease that is somewhat unusual in the formation of bullae in the lower lobe, in contradistinction to its marked upper lobe predominance.