Although respiratory insufficiency is common in the advanced stages of motor neuron disease, some patients may develop distressing respiratory symptoms early in the course of the disease or even present with respiratory failure or arrest. We describe 14 patients with motor neuron disease who were considered for respiratory support; 11 received such support and all derived significant symptomatic improvement without distressing prolongation of life. Of the 8 patients with typical features of amyotrophic lateral sclerosis, 7 had predominant diaphragm weakness and 1 generalized respiratory muscle weakness; 7 received negative pressure ventilation by cuirass which improved both the quality of sleep and exercise tolerance. Three patients with predominantly bulbar disease had nocturnal apnoea or hypoventilation. Two received no support. One, who also developed diaphragm weakness, was treated by a cuirass, continuous positive airway pressure (CPAP), and later nocturnal intermittent positive pressure ventilation (IPPV). Three patients with progressive muscular atrophy had predominant diaphragm weakness or nocturnal apnoea. These patients received nocturnal CPAP, cuirass or IPPV with symptomatic benefit. This series shows that some patients with motor neuron disease, mainly those with symptoms due to respiratory muscle weakness in the absence of severe bulbar impairment, derive symptomatic benefit from supported ventilation.