Phrenic nerve palsy leads to disfunction of the main respiratory muscle. With bilateral palsy dyspnoea in the supine body position will typically occur. With one-sided lesion symptoms will only appear when a second pulmonary disease is present.We refer of 6 patients with bilateral and 5 with unilateral diaphragmatic paresis. In 3 patients neuralgic shoulder-arm-amyotrophy was diagnosed, in further 4 there was suspicion of it. Amyotrophic lateral sclerosis developed in 2 after 4 respectively 8 months. In 1 case a cervical operation led to palsy, mediastinitis in 1 case. Lung function tests showed a restrictive pattern, especially in bilateral palsy.Vital capacity was reduced by almost 50% respectively 25% in the supine body position. Mouth occlusion pressure reduction was apparent. Near normal to marked hyperkapnia developed in bilateral paresis. In 5 cases non-invasive intermittent ventilation is instituted (2 volume controlled, 3 pressure supported). Two patients died (1 patient with amyotrophic lateral sclerosis after 13 months, 1 with malignant pleurisy after 4 months). Three patients continued non-invasive intermittent ventilation since 14 to 64 months.