The introduction of NPPV has been one of the most important advances in the management of patients at home with chronic respiratory failure. The benefit obtained from the therapy depends, however, on the underlying cause of the respiratory failure. Patients with chest wall disease and postpolimyelitis show the best improvements in survival and quality of life. But even in patients with Duchenne muscular dystrophy, useful benefits for survival and quality of life are obtained. The longer-term effects of NPPV in hypercapnic COPD are not so clear, and further large, well-designed controlled studies are required to evaluate the effects of NPPV not only on survival, but also on quality of life and disease exacerbation. If the initial experience with NPPV in COPD is confirmed in larger trials, then this important therapy will be available to an even larger group of patients worldwide.