Non-invasive ventilation (NIV) via nasal or full face mask can be applied in respiratory failure due to chronic obstructive pulmonary disease (COPD) both in the acute and long-term settings. In acute exacerbation of COPD with respiratory failure it may be considered as a standard treatment. There is strong evidence that NIV might reduce intubation, complication, and mortality rate in patients with acute hypercapnia (PaCO(2) >45 mmHg). The method is cost effective and reduces hospital stay. NIV might be also useful in the weaning of COPD patients from invasive ventilation. On the other hand, for severe stable disease the data concerning a positive effect of NIV are less convincing. Preliminary evidence suggests that NIV improves gas exchange, sleep quality and quality of life and might reduce the need for hospitalization. Especially, COPD patients with substantial chronic hypercapnia (PaCO(2) >55 mmHg) and/or nocturnal hypoventilation, and those with repeated exacerbations may profit from NIV. In any case, NIV is a very valuable and effective tool in the non-pharmacological treatment of COPD. Every clinician who is involved in the management of COPD patients with respiratory insufficiency should be able to apply this technique.