Ultrasound (US) is an ideal diagnostic tool for paediatric patients owning to its high spatial and temporal resolution, real-time imaging, and lack of ionizing radiation and bedside availability. The lack of superficial adipose tissue and favorable acoustic windows in children makes US the first line of investigation for the evaluation of pleural and chest wall abnormali-ties. Lung parenchyma was previously thought to be inaccessible to ultrasound due to the presence of the air and bony thorax. The change in attitude and growing awareness of the diagnostic possibilities has led to lung ultrasound (LUS) being accepted as a valuable point of care method. In addition, the application of LUS has widened with improvements in technology such as higher resolution transducers, harmonic imaging and contrast-enhanced ultrasound. In the current World Federation of Societies for Ultrasound in Medicine and Biology (WFUMB) paper series the topic will be introduced, the technical requirements explained and the use of ultrasound in the lung and pleura in pediatric patients are discussed.