Intermittent mechanical ventilation via nasal CPAP mask was provided to 13 patients admitted to this institution for exacerbation of chronic respiratory failure. Ten suffered from COPD, two suffered from obesity hypoventilation syndrome (OHS), and one from severe hypothyroidism. All except one presented with dyspnea and hypercapnia due solely to progression of their underlying disease processes. Six of the patients with COPD and the patient with hypothyroidism responded to positive pressure ventilation by mask with improvements in blood gas values and clinical status. The remaining two patients with COPD and the two patients with OHS were unable to use the system. Four of the patients with COPD and chronic respiratory failure have been subsequently maintained on daily volume ventilation via nasal mask for about 20 months with persistent clinical and physiologic improvements. Application of volume ventilation through the nasal CPAP mask is a feasible strategy for providing long-term mechanical ventilation to selected patients with COPD and respiratory failure.