Thoracic sonography has become an established imaging tool for evaluating specific paediatric thoracic diseases; particularly queries such as thymomegaly, pleural effusion, pulmonal sequester or thoracic small part pathology may be reliably addressed. Using appropriate ultrasound equipment the well trained and experienced investigator may diagnose these conditions without the need for a radiating imaging modality or help to evaluate equivocal findings on chest plain films. The important requisites as well as the established disease entities that pose an indication for thoracic ultrasound are listed and described. The restrictions and setbacks are discussed, and an algorithm for additional imaging and typical scenarios is supposed in order to help and encourage the meaningful and efficient use of this non-ionising, easy applicable imaging tool to chest queries. In conclusion, this review tries to give an overview of the restrictions and indications for thoracic sonography in neonates, infants and children as a useful imaging tool when indicated.