The aim was to study the efficacy of rescue High Frequency Oscillatory Ventilation (HFOV) in improving the oxygenation and ventilation in neonates with acute respiratory failure after failing Conventional Mechanical Ventilation (CMV). Primary outcome was short term oxygenation, lung recruitment, and ventilation and secondary outcome studied was survival. 675 babies were ventilated and 97 of them received HFOV. HFOV significantly improved oxygenation index, alveolar-arterial oxygen gradient, pH, PCO2, PO2 and caused better lung recruitment within 2 hours. Fifty seven babies (58.77%) survived and the mortality was more in <28 weeks, babies with pulmonary hemorrhage, sepsis and CDH.