Hyaline membrane disease (HMD) is one of the most common causes of respiratory distress in premature neonates. The most serious complications of prematurity and associated HMD with neonatal mechanical ventilation is bronchopulmonary dysplasia (BPD) which characterized by chronic respiratory signs, persistent oxygen requirement, and an abnormal chest X-ray at 1 month of age postnatal or at 36 weeks corrected age. To determine the importance of lungs ultrasound (US) in prediction of BPD development in neonates with HMD and to detect the earliest neonatal age for BPD development diagnosis. A prospective descriptive study done on 85 preterm newborns with respiratory distress syndrome, admitted in neonatal intensive care unit (NICU) in El Galaa teaching hospital in Cairo, from November 2020 to March 2021. The study included: Preterm neonates (< 37 weeks gestation), having respiratory distress syndrome (RDS) whether mechanically ventilated or not with maternal history of antenatal corticosteroid administration. We excluded: Full term neonates, respiratory distress of causes other than respiratory distress syndrome, congenital anomalies, metabolic disorders or suspected inborn errors of metabolism and neurological causes leading to hyperventilation like seizures. The aim of first US examination is to determine RDS US pattern presence or absence. This was done initially on admission during the first 3 days of life. The subsequent examinations done twice weekly were for follow up. The US pattern correlated with the clinical and radiographic pattern of BPD at or after 28 days of life. Twenty (23.6%) preterm neonates developed BPD clinically and radiologically, they were 13(65%) males and 7(35%) females, with mean gestational age 32.3±2.2 weeks, whether they were mechanically ventilated or not. Nine (10.6%) preterm neonates died within the first three weeks of life, they were 5(55.5%) males and 4(44.5%) females with mean gestational age 31.6±2.1weeks. Ultrasound examination of the lung done in the period (9th-13th day postnatal) has a high predictive value for subsequent development of BPD. Lung US may be utilized in ventilated preterm neonates for early prediction of BPD in the period (9th-13th day postnatal) where persistence of the abnormal retro diaphragmatic hyper echogenicity by this time is a predictor for the future development of BPD.