Background: Understanding the epidemiology and prevalence of febrile urinary tract infection (fUTI) in children is important for risk stratification and selecting appropriate urine sample collection candidates to aid in its diagnosis and treatment.Purpose: This study aimed to analyze the epidemiology, etiology, and changes in antibiotic susceptibility patterns of the first fUTI in children.Methods: This retrospective observational cohort study included children younger than 19 years of age who were diagnosed and treated for their first fUTI in 2006–2016. Electronic medical records were analyzed and radiologic images were evaluated.Results: A total of 359 patients (median age, 5.1 months; interquartile range, 3.0–10.5 months) fit the inclusion criteria; of them, 78.0% (n=280) were younger than 12 months old. The male to female ratio was 5.3:1 for patients aged 0–2 months, 2.1:1 for those 3–5 months, and 1.6:1 for those 6–11 months. Beyond 12 months of age, there was a female predominance. <i>Escherichia coli</i> was the leading cause (83.8%), followed by <i>Enterococcus species</i> (6.7%), and <i>Klebsiella pneumoniae</i> (3.6%). Significant yearly increases in the proportions of multidrug-resistant strains (<i>P</i><0.001) and extended-spectrum beta-lactamase (ESBL) producers (<i>P</i><0.001) were observed. In patients with vesicoureteral reflux (VUR), the overall recurrence rate was 53.6% (n=15). A significantly higher recurrence rate was observed when the fUTI was caused by an ESBL versus non-ESBL producer (75.0% vs. 30.0%, <i>P</i>=0.03).Conclusion: fUTI was most prevalent in children younger than 12 months of age and showed a female predominance in patients older than 12 months of age. The proportion of ESBL producers causing fUTI is increasing. Carbapenems, rather than noncarbapenems, should be considered for treating fUTI caused by ESBL-producing enteric gram-negative rods to reduce short-term recurrence rates in children with VUR.