Antimicrobial resistance (AMR) poses a critical threat to pediatric health, particularly in resourcelimited settings. This study aimed to evaluate the association between the maturity of antimicrobial stewardship programs (ASPs) and clinical outcomes in Peruvian hospitals. A multicenter, retrospective cohort study was conducted in three pediatric referral hospitals in Peru, including 1,250 patients hospitalized for bloodstream or urinary tract infections between 2020 and 2023. Multilevel logistic regression models and propensity score matching (PSM) analysis were used to assess risk factors for infections caused by extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae and the impact of ASP intervention. The prevalence of ESBL-producing Enterobacteriaceae infection was 32.9% in the three pediatric hospitals of this study. Prior antibiotic use (adjusted Odds Ratio, aOR 5.82) and the presence of a central venous catheter (aOR 2.10) were the main patient-level risk factors. Higher ASP maturity at the hospital level was associated with a lower likelihood of ESBL infection (aOR 0.85). PSM analysis revealed that direct ASP intervention was associated with a significant reduction in hospital length of stay (median of 3 days), 30-day mortality (4.2% difference), and time to appropriate therapy. In conclusion, pediatric AMR in Peru is a severe problem, but investment in and strengthening of ASPs constitute an evidence-based, highly effective strategy with a measurable impact on improving clinical outcomes and hospital efficiency.  Kulcsszavak: antimicrobial resistance, pediatrics, antimicrobial stewardship, extended-spectrum beta-lactamases (ESBL), Peru