A critical review of the most recent literature regarding use and clinical indications of noninvasive mechanical ventilation (NIV).According to several randomized controlled trials, NIV has gained acceptance as the preferred ventilatory modality to treat acute respiratory failure (ARF) due to chronic obstructive pulmonary disease exacerbations, cardiogenic pulmonary edema, respiratory failure in immunocompromised patients, and to decrease the intubation length and to improve weaning results in patients recovering from a hypercapnic respiratory failure. Observational studies suggest that NIV may also be used to treat other conditions like severe pneumonia (including H1N1 virus), severe asthma attack, cystic fibrosis, obesity hypoventilation, and to improve the respiratory outcome in postsurgical patients.NIV has radically changed the management of ARF. Recently the possible applications of NIV have increased, both in the hospital and extrahospital setting. NIV is no longer confined to the ICU, but has crossed over into the regular ward, Emergency Department and 'out-of-hospital' environment. Current research is focusing on improving the quality and safety of the devices and establishing new ventilatory modes in order to extend even further the indications to NIV as well as its rate of success.