Non-invasive ventilation (NIV) is a method of respiratory support that is commonly used for the management of a wide range of causes of respiratory failure, both within and without the intensive care unit (ICU). This review will discuss the advantages of this mode of ventilation over more traditional methods, its indications and contra-indications and the equipment required, as well as reviewing the available literature for evidence of its efficacy. NIV is also used in the management of chronic respiratory failure caused by either pulmonary disease or neurological conditions – this will not be considered further by this review.