Respiratory distress syndrome (RDS) is the main cause of respiratory failure in preterm neonates, its incidence varying from 80% to 25% depending on gestational age.When optimal prenatal care is provided, the best approach to treat RDS, according to several recent trials,consists in providing continuous positive airway pressure (CPAP) from the first minutes of life using short binasal prongs or masks, followed by early selective surfactant administration for babies with worsening oxygenation and/or increasing work of breathing. Any effort should be done to minimize the time under invasive mechanical ventilation (IMV).Nonetheless, clinical trials have shown that a relevant proportion of preterm neonates fails this approach and eventually need IMV.The duration of IMV is a well known risk factor for the development of broncho-pulmonary dysplasia (BPD) - a condition associated with significant morbidity and mortality. To minimize the duration of IMV, various non invasive respiratory support modalities are available in neonatal intensive care units (NICU). CPAP is presently the most common technique used in this regard. However, a systematic review has shown that non-invasive positive pressure ventilation (NIPPV) reduces the need for IMV (within one week from extubation) more effectively than NCPAP, although it is not clear if NIPPV may reduce need for intubation longterm and it seems to have no effect on BPD and mortality. NIPPV main drawback is the lack of synchronization, which is difficult to be accurately achieved and is usually unavailable. A more recent alternative technique is non-invasive high frequency oscillatory ventilation (NHFOV) which consists on the application of a bias flow generating a continuous distending positive pressure with oscillations superimposed on spontaneous tidal breathing with no need for synchronization. The physiological, biological and clinical details about NHFOV have been described elsewhere. To date, there is only one small observational uncontrolled study about the use of NHFOV after extubation in preterm infants. Other relatively small case series or retrospective cohort studies suggested safety, feasibility and possible usefulness of NHFOV and have been reviewed elsewhere.The only randomized trial published so far compared NHFOV to biphasic CPAP,in babies failing CPAP and it has been criticized for methodological flaws and for not taking into account respiratory physiology.An European survey showed that, despite the absence of large randomized clinical trials, NHFOV is quite widely used, at least in some Countries and no major side effects are reported, although large data about NHFOV safety are lacking. This may be due to the relative NHFOV easiness of use but evidence-based and physiology-driven data are warranted about this technique.