Background: Acute kidney injury (AKI) is a major contributor to morbidity and mortality among critically ill children. Understanding the epidemiology and determinants of AKI in resourcelimited paediatric intensive care units (PICUs) is essential for targeted prevention and management strategies. Objectives: To determine the incidence, aetiology , risk factors and clinical outcomes of AKI among children admitted to a tertiary care PICU in Sri Lanka. Methods: A descriptive observational study was conducted among 260 consecutive PICU admissions. AKI was identified and staged using KDIGO criteria. This study was funded by the research grant awarded by the Sri Lanka Society of Nephrology . Results: AKI occurred in 57 children, giving an incidence of 21.9%. AKI was predominantly prerenal in origin (75.4%) and sepsis was the main aetiology . Majority (49.1%) had AKI stage 3. Requirement for inotropic support was significantly associated with AKI (p = 2.87 × 10? ? ).Clinical outcomes among AKI patients were poor: 52.6% achieved complete renal recovery, 3.5% had partial recovery , while 43.9% died, compared to the overall PICU mortality rate of 17 .7%. Markedly higher death rate in the AKI group compared to non-AKI patients (p = 1.40 × 10? ? ).Mortality was particularly associated with higher AKI stage (p = 0.019). Only 1.5% of the total cohort underwent RRT. Exposure to nephrotoxic medications was high among AKI patients (77 .2%), (p = 0.168). Conclusion: AKI affects nearly one in five critically ill children in this tertiary care PICU and is characterised by predominantly pre-renal aetiology , high disease severity , and significantly increased mortality .