REVIEWChildren and especially infants are not small adults -they suffer from specific diseases, present different imaging demands and have increased radiation sensitivity. One important aspect of ongoing continuous improvement of medical imaging is the increasing potential of ultrasound (US); this may help to minimize radiation by replacing or obviating other imaging. This important task, particularly in childhood, can only be achieved by providing dedicated skilled pediatric US to children 24 h, 7 days a week.The purpose of this review is to give some key advice on pediatric US, to list and illustrate typical pediatric conditions, to debate the relevant respective differential diagnoses and how US can reliably provide diagnostically relevant information with implications on therapy. For those who are familiar with pediatric radiology the following should be a useful review with some highlighted details. For everyone else this review should demonstrate what is achievable by modern US in children, completely different from the US potential in (obese) adult patients. We will aim to point out the significance of US in common and important pediatric abdominal queries and emphasize the difference between adults and children not only in terms of pathology, but also in the application and potential of the modality itself.Ultrasound (US) has gained its place as the preferred first-line imaging modality in the child's abdomen. Especially in infants US has advantages -the small amount of tissue and fat creating restrictions to CT and MRI allows for application of high-resolution (especially linear) transducers, offering excellent imaging capabilities; in addition, US is applicable at the bedside and can be performed without sedation. As radiation protection has become a key issue for imaging children, exploiting US to the utmost using all its possibilities and applying modern methods that have significantly widened US potential is an indispensable and increasingly important approach. This review illustrates standard US techniques, basic and new applications throughout the entire abdomen and its different organ systems, trying to point out the enormous potential of US in different clinical scenarios, focusing on gastrointestinal and urogenital issues. Future perspectives provided by new modalities such as contrastenhanced and 3D US will further strengthen the diagnostic value of this powerful imaging tool, hopefully contributing to continuing reduction of diagnostic radiation burden to children, by diminishing the need for CT. KEYWORDS: abdomen n children n gastrointestinal n infants n pediatric ultrasound n urinary tract