BACKGROUND The non-invasive technique of nasal intermittent positive pressure ventilation (NIPPV) has an established role in providing domiciliary nocturnal ventilatory support in patients with chest wall disorders, neuromuscular disease, and chronic obstructive lung disease. NIPPV was used to simplify ventilatory management and assist the return of spontaneous breathing in patients with chronic respiratory insufficiency who had failed to wean from conventional intermittent positive pressure ventilation (IPPV). METHODS A trial of NIPPV was carried out in 22 patients with weaning difficulties. Nine patients had chest wall disorders or primary lung disease, six had neuromuscular conditions, and seven had cardiac disorders with additional pulmonary disease. Conventional IPPV via an endotracheal tube or tracheostomy had been continued postoperatively in nine patients and 13 had been ventilated after acute cardiorespiratory decompensation. RESULTS Conventional IPPV had been continued for a median of 31 days (range 2-219). Eighteen patients were successfully transferred to NIPPV and discharged home a median of 11 days (range 8-13) after starting this type of ventilation. Sixteen patients remain well 1-50 months after hospital discharge and 10 of these continue on domiciliary nocturnal NIPPV. Seven patients have returned to work. CONCLUSIONS NIPPV can be used to facilitate the return of spontaneous breathing and to reduce the need for intensive care accommodation in patients with an acute exacerbation of chronic respiratory insufficiency that requires intubation and IPPV.