Invasive ventilation is related to development of adverse pulmonary and nonpulmonary outcomes in ventilated infants. Various modes of noninvasive respiratory support are being increasingly used to minimize the incidence of bronchopulmonary dysplasia (BPD). The aim of this trial to compare the effects of noninvasive high frequency oscillatory ventilation (NHFOV) and nasal continuous positive airway pressure (NCPAP) in preterm twins infants as the primary mode.