IMPORTANCEUrinary tract infections (UTIs) are one of the most commonly diagnosed infections, and prior studies have reported discordance in antibiotic treatment with the Infectious Diseases Society of America (IDSA) guidelines. OBJECTIVE To assess IDSA guideline concordance rates for women with uncomplicated UTIs treated with antibiotics, and compare concordance rates between different specialty field. DESIGN, SETTING, AND PARTICIPANTS Retrospective cross-sectional study of health care claims data from the US Military Health System Data Repository, which contains comprehensive health care encounter and claims data for all military beneficiaries. Participants were adult women between the ages of 18 to 50 years with uncomplicated UTIs from October 1, 2017, to September 30, 2019. Data extraction and analysis were performed in 2022. Patients with diagnosis of UTI in the preceding 6 months, current pregnancy, history of pyelonephritis, history of diabetes, history of organ transplant, history of human immunodeficiency virus, immunosuppression, renal insufficiency, urinary tract abnormalities, or history of urologic procedures were excluded. EXPOSURES Antibiotic treatment for uncomplicated UTIs. Only antibiotics received within 1 day after the diagnosis were analyzed. The IDSA recommends the following antibiotics as first-line therapy: nitrofurantoin, trimethoprim-sulfamethoxazole, fosfomycin, pivmecillinam. MAIN OUTCOMES AND MEASURES The IDSA guideline concordance rates were calculated as the number of patients receiving first-line antibiotic therapy divided by the total number of cases for uncomplicated UTIs. RESULTS A total of 46 793 adult women (67.3% [31 475 of 46 793] aged 18-34 years; 38.2% [31 475 of 46 793] of White race) were diagnosed with uncomplicated UTIs with 91.0% receiving guidelineconcordant antibiotic treatment. In comparison with obstetrics and gynecology, IDSA guidelineconcordant treatment was more likely in internal medicine (adjusted odds ratio [aOR], 2.87; 95% CI,