During the last 25 years, the use of non-invasive ventilation has grown substantially. Non-invasive ventilation refers to the delivery of positive pressure to the lungs without endotracheal intubation and plays a significant role in the treatment of patients with acute respiratory failure and in the domiciliary management of some chronic respiratory and sleep disorders. In the intensive and acute care setting, the primary aim of non-invasive ventilation is to avoid intubation, and it is mainly used in patients with chronic obstructive pulmonary disease exacerbations, acute cardiogenic pulmonary oedema, immunocompromised or in the context of weaning, situations in which a reduction in mortality has been demonstrated. The principal techniques are continuous positive airway pressure, bilevel pressure support ventilation and more recently, high flow nasal cannula. Whereas non-invasive pressure support ventilation requires a ventilator, the other two techniques are simpler and can be easily used in non-equipped areas by less experienced teams, including the pre-hospital setting. The success of non-invasive ventilation is related to an adequate timing, proper selection of patients and interfaces, close monitoring as well as the achievement of a good adaptation to patients’ demand.