Background: Acute kidney injury (AKI) is defined as an abrupt onset of renal dysfunction resulting from injurious endogenous or exogenous processes characterized by a decrease in glomerular filtration rate (GFR) and an increase in serum creatinine. AKI is common in critically ill children and early diagnosis is important for better outcome in these children.Methods: This was a prospective observational study. Critically ill infants and children of either sex and in age group between >28 days to 12 years admitted to pediatric intensive care unit (PICU) were included. Serum creatinine and estimated creatinine clearance (eCC) were used to and patients classified as AKI on pRIFLE criteria either at admission or subsequently during the hospital stay. AKI cases were further classified into risk, injury or failure category on the day of development of AKI and the maximum pRIFLE stage reached during PICU stay was noted. Detailed data regarding the treatment received and use of nephrotoxic drugs, inotropic support, mechanical ventilation, dialysis and total length of stay in PICU in all was noted. Outcome of the subjects were observed for survival or mortality.Results: Total 343 subjects were enrolled in the study. During the study 27.1% patients developed AKI according to pRIFLE staging. In AKI category 60.21% reached maximum risk category, 21.5% reached maximum injury category, 18.28% reached maximum failure category. Amongst AKI subjects 64.52% had infectious etiology. Multiorgan dysfunction, encephalopathy, shock, metabolic acidosis, hypertension, mechanical ventilation and nephrotoxic drugs administration were more associated with AKI and was statistically significant.Conclusions: Pediatric modification of RIFLE criteria is sensitive index to detect AKI at earliest in critically ill children for early intervention leading to better outcome.