Bowel ultrasound (US) is a low-cost, non-invasive, bed side practice and a reproducible procedure that represents a high yield tool in clinical practice and in the diagnostic workup of a consistent group of acute and chronic gastrointestinal (GI) tract disease. Moreover, in case of GI diseases of neonatal and pediatric age, it allows an easier evaluation due to the small body size and scarce presence of fat tissue in the abdominal wall and peritoneal cavity and gas content. No particular preparation of the patient is needed, nevertheless a 3- to 5-hour fasting state improves the quality of the examination. The exam focuses on wall thickness and stratification, lumen content, distensibility and compressibility, presence of peristalsis of explorable segment of the GI tract and includes the investigation of mesentery, perivisceral tissues and nodes features. Color doppler flowmetry admits a qualitative evaluation of GI wall and mesentery vascularization. Healthy GI wall appears at a US evaluation as a multilayered structure in which hyperechoic and hypoechoic layers alternate sequentially. In this article we provide a quickly available overview on findings, signs and applications of US in major GI pediatric diseases.