Positive end-expiratory pressure (PEEP) is used during non-invasive and invasive ventilation of newborns, infants and children. PEEP improves gas exchange by increasing the functional residual capacity, reduces the respiratory effort, lowers requirements for respiratory mixture oxygen, and enables to decrease the peak inspiratory pressure (PIP) without decreasing the mean airway pressure. Its effects on the cardiovascular system appear to be insignificant, particularly in patients with severe respiratory failure that is not accompanied by circulatory insufficiency. The value of PEEP enabling to provide the optimal conditions for improvement of gas exchange should be tailored individually for each patient under control of blood gas analysis, PIP and FiO₂. This strategy minimises ventilator-induced lung injury and prevents the development of circulatory failure associated with ventilation. Nasal continuous positive airway pressure (NCPAP) used with various PEEP values is a recognised treatment method of respiratory failure in newborns, especially in preterm infants.