Background: This study set out to (1) describe the ultrasound features of non traumatic acute abdomen (NTA) among paediatric patients at Mulago National Referral Hospital (MNRH); (2) to describe the common clinical presentations of NTA paediatric emergencies at MNRH; (3) to relate the clinical features with ultrasound findings and lastly (4) to relate the ultrasound findings with the final diagnosis (whether surgically or medically managed). Materials and methods: A prospective cross sectional study was carried out. Eighty-seven paediatric patients (12 years and below) who were sent for ultrasound scan of the abdomen following an initial clinical impression of acute abdomen were scanned at MNRH radiology department between March 2015 and March 2016. Linear and a curvilinear probes from a Samsung Medison Sonoace R7 Ultrasound machine model 2013 were used. To answer the research questions, categorical variables were summarized using proportions. Continuous variables were summarized by computing the median and range. Results: The commonest clinical presentations of children with NTA besides abdominal pain werefever (69%) and vomiting (67%). The patients who presented with vomiting were more likely to have positive US findings. The commonest ultrasound findings were mesenteric lymphadenitis 18 (21.1%), ascites 14 (16.8%) and pneumoperitonium(10.6%).The most common US diagnosis in infants was intussusception 6 (29%), while children 1-3 years were mostly diagnosed with mesenteric lymphadenitis 3(27%) and ascites 3(27%), those aged between 4-7 years 6 (40%); 8-12 years 7 (25%) were mostly diagnosed with mesenteric lymphadenitis. Conclusion: The commonest ultrasound findings were mesenteric lymphadenitis, ascites and pneumoperitonium. The most common US diagnosis in infants was intussusception 6 (29%), while children 1-3 years were mostly diagnosed with mesenteric lymphadenitis 3(27%) and ascites 3(27%), those aged between 4-7 years 6 (40%); 8-12 years 7 (25%) were mostl