Current criteria for surfactant administration assume that hypoxia is a direct marker of lung-volume de-recruitment. We first introduced an early, non-invasive assessment of lung mechanics by the Forced Oscillation Technique (FOT) and evaluated its role in predicting the need for surfactant therapy. To evaluate whether lung reactance (Xrs) assessment by FOT within 2 h of birth identifies infants who would need surfactant within 24 h; to eventually determine Xrs performance and a cut-off value for early detection of infants requiring surfactant. We conducted a prospective, observational, non-randomized study in our tertiary NICU in Milan. Eligible infants were born between 27 and 34  weeks' gestation, presenting respiratory distress after birth. endotracheal intubation at birth, major malformations participation in other interventional trials, parental consent denied. We assessed Xrs during nasal CPAP at 5 cmH O at 10 Hz within 2 h of life, recording flow and pressure tracing through a Fabian Ventilator for off-line analysis. Clinicians were blinded to FOT results. We enrolled 61 infants, with a median IQR gestational age of 31.9 30.3; 32.9 weeks and birth weight 1490 1230; 1816 g; 2 infants were excluded from the analysis for set-up malfunctioning. 14/59 infants received surfactant within 24 h. Xrs predicted surfactant need with a cut-off - 33.4 cmH O*s/L and AUC-ROC = 0.86 (0.76-0.96), with sensitivity 0.85 and specificity 0.83. An Xrs cut-off value of - 23.3 cmH O*s/L identified infants needing surfactant or respiratory support > 28 days with AUC-ROC = 0.89 (0.81-0.97), sensitivity 0.86 and specificity 0.77. Interestingly, 12 infants with Xrs < - 23.3 cmH O*s/L (i.e. de-recruited lungs) did not receive surfactant and subsequently required prolonged respiratory support. Xrs assessed within 2 h of life predicts surfactant need and respiratory support duration in preterm infants. The possible role of Xrs in improving the individualization of respiratory management in preterm infants deserves further investigation.