Due to the its great morbidity and mortality, home mechanical ventilation via tracheotomy is reserved, as a mandatory support, just to the patients with chronic obstructive pulmonary disease (COPD), who, after an episode of acute respiratory failure, cannot acquire a full ventilatory autonomy. During the last two decades the potential benefits of non-invasive ventilation (NIV) as a domiciliary treatment of severe COPD with CO2 retention have been investigated. Patho-physiologic basis of its employ are resting of respiratory muscles and/or resetting of respiratory centres. Due to its poor tolerability, negative pressure NIV has been taken over by positive pressure technique. As the results of the few available controlled studies obtained with the latter ventilatory technique aren't very enthusiastic and univocal, it's not possible to draw clear guidelines about the domiciliary use of NIV in COPD. In conclusion, the author suggests that, in order to avoid useless waste of resources, the application of NIV to stable COPD should be reserved to very selected cases (significant hypercapnia, frequent nocturnal desaturations and/or sleep disordered breathing and/ or hospital admissions) with demonstrated effectiveness and adequate compliance to the treatment. With the aim of better define the real field of application of home NIV in stable COPD, further and larger studies are needed having as end-points not only the crude survival and the lung functional data but also the quality of life of the patient and the impact upon the health expenses.