Lung ultrasound (LU) is becoming a bedside point-of-care technique in critical care and emergency medicine as it is performed and immediately interpreted by the clinician. LU is quick, easy, relatively inexpensive, and provides accurate diagnostic information when compared with conventional lung imaging methods, such as CT scans and chest radiographs, with the additional advantage of being non-irradiating, adapted to bedside use, and easily repeatable with no side effects for the patient. LU is easy to learn, does not require sophisticated ultrasound machines or settings, and shows low intra- and interobserver variability when a standardized approach is used. A comprehensive and standardized ultrasound semiology has been described and validated in both adults and children. In summary, LU allows for quick easy recognition of a normally aerated lung in contrast to an interstitial or alveolar pattern. Recognition of these patterns may be even easier in neonates due to their small size and the absence of obesity and heavy musculature. Specific LU findings have been described for some types of neonatal lung injury, such as neonatal respiratory distress syndrome, transient tachypnea of the neonate, meconium aspiration syndrome, and neonatal pneumonia. In the newborn, LU has proved its usefulness in predicting the need for hospital admission and/or intubation based on simple LU patterns. A recently proposed LU score, adapted for the neonate, correlates well with oxygenation status, independently of gestational age and underlying respiratory condition. The score reliably predicts the need for surfactant treatment in preterm babies less than 34 weeks gestation treated with nasal CPAP from birth. LU is a promising tool with numerous potential applications that warrant future studies. However, like every technique, LU has its limitations and should not completely replace standard radiography. LU can nevertheless largely reduce exposure to ionizing radiation by limiting the use of conventional radiographs to a strict minimum.