Clinical studies have shown that noninvasive positive pressure ventilation (NPPV) have significant advantages in the treatment of respiratory failure due to COPD. Reduced intubation need, decreased complications and mortality and less hospitalization in intensive care unit are recognized benefits of NPPV. A general consensus has been reached that NPPV application in acute respiratory failure can decrease respiratory muscles effort and improve gas exchange, when performed in selected patients by an expert team. Application of long term NPPV in patients with advanced stable COPD and chronic CO2 retention is still controversial. The contrasting results were obtained from studies with small patients number, short time observation and different patient's selection. Therefore randomized and controlled studies with a great number of patients are essential to evaluate the effects of NPPV in stable COPD patients with chronic retention of CO2, not only in survival but also in quality of life.