Objective: To identify factors associated with the length of hospital stay among pediatric patients with urinary tract infections (UTIs) caused by extended-spectrum β-lactamase-producing Enterobacteriaceae (ESBL-E) in two Peruvian hospitals. Materials andmethods: A retrospective cohort study was conducted through a review of medical records of children with UTIs caused by ESBL-E hospitalized between 2016 and 2022 at Hospital Nacional Edgardo Rebagliati Martins (Seguro Social de Salud [EsSalud] – Peru’s Social Health Insurance) and Hospital Nacional Docente Madre Niño San Bartolomé (Ministerio de Salud [MINSA] – Ministry of Health). The primary outcome variable was the length of hospital stay, defined as the number of days between admission and discharge. Linear regression with logarithmic transformation was used to identify factors associated with longer hospital stays. Addition...