Acute kidney injury (AKI) and sepsis are both associated with morbidity and mortality in critically ill patients. In detail, critically ill children with severe AKI (KDIGO stage 2 or 3) had a higher 28-day mortality than children without severe AKI (11% vs. 2.5%) and sepsis-associated AKI (SA-AKI) was independently associated with increased odds of mortality in a large cohort of children with septic shock [1,2]. Furthermore, the incidence of SA-AKI has increased over the past two decades, affecting mortality, hospitalization, and costs in this population [3]. Thus, early recognition of children at higher risk of developing SA-AKI could potentially be effective in improving septic patients' management and outcomes.In a recent paper in Pediatric Nephrology, Stanski and colleagues presented the results of a secondary analysis of a large, prospective, observational study, looking at the impact of elevated serum renin + prorenin concentration as a predictor of persistent AKI and mortality in children with septic shock [4]. In a cohort of 233 critically ill children with septic shock, an elevated renin + prorenin concentration at day 1 was predictive of severe persistent AKI in the first week of pediatric intensive care unit (ICU) stay. Similarly, persistence of renin + prorenin elevation at day 3 (as quantified by day 3:day 1 renin + prorenin ratio above an optimal cutoff) was predictive of 28-day mortality [4]. Therefore, the authors suggested that renin may be a valuable prognostic and predictive biomarker in pediatric critically ill patients with septic shock, which, if confirmed by further studies, may potentially guide therapy and improve outcomes in this population.