High frequency ventilation (HFV) is a mode of therapy that improves gas exchange with pressure fluctuations much lower than that required for conventional ventilation. HFV is efficacious in the "rescue" management of infants with respiratory failure. Although each HFV system has functional characteristics that are design related, it now appears that when used with similar treatment strategies and within functional limitations, similar outcomes can be achieved. Ideally, the clinician or the operator should be familiar with the basic concepts of different high frequency ventilators to achieve maximal benefits from using these devices in infants with respiratory failure.