High frequency oscillatory ventilation (HFOV) has emerged over the past 20 years as a safe and effective means of mechanical ventilatory support in patients with acute respiratory failure. During HFOV, lung recruitment is maintained by application of a relatively high mean airway pressure with superimposed pressure oscillations at a frequency of 3 to 15Hz, creating adequate ventilation using tidal volumes less than or equal to the patient's dead space volume. The physiologic rationale for the application of HFOV in the clinical arena comes from its ability to preserve end-expiratory lung volume while avoiding parenchymal overdistension at end-inspiration and theoretically limiting the potential for ventilator-associated lung injury. Data in the neonatal population suggests significant benefits in pulmonary outcomes when HFOV is applied with a recruitment strategy in preterm infants with respiratory distress syndrome (RDS). Use of HFOV in the paediatric and adult populations has not as yet been associated with significant improvements in clinically important outcome measures.