INTRODUCTION: Invasive fungal infections (IFI) in paediatric oncology patients are associated with significant morbidity and mortality. Abdominal ultrasonography is widely used for diagnosis, but its utility remains unclear. METHODS: We conducted a retrospective cohort study of paediatric oncology patients who were febrile and neutropaenic at Queensland Children's Hospital, Australia, from January 2018 to December 2019. We reviewed abdominal ultrasound (US) examinations requested for suspected IFI, analysing diagnostic yield and associations with clinical variables. RESULTS: There were 94 patients included, 21 of whom did not survive their underlying condition, seven (7.4 %) showed evidence of IFI on US. Infections did not demonstrate a predilection for a particular abdominal organ. Fourteen patients had a positive blood culture, with only three confirmed fungal pathogens. Chest computed tomography, performed in 41 of cases had findings suspicious for IFI in 52.3 % of these examinations. CONCLUSION: Abdominal ultrasonography has a low diagnostic yield (7.4 %) for new IFI in paediatric oncology patients. However, given the mortality rate in this population, its use may be justified for monitoring known infections and as part of a comprehensive diagnostic approach. IMPLICATIONS FOR PRACTICE: US is an effective method of screening for abdominal IFI in paediatric oncology patients who are febrile and neutropaenic. The low diagnostic yield is outweighed by the morbidity and mortality of IFI in this vulnerable patient cohort.