en علوم پایه پزشکی Basic medical sciences پژوهشي Research <strong>Background and objectives: </strong>Diagnosis and treatment of urinary tract infection (UTI) in children before kidney damage is necessary. The purpose of this study was to compare efficacy of co-trimoxazole and cephalexin in the prevention of recurrent UTI in children.<br> <strong>Methods:</strong> The study was performed on 100 children aged three months to 14 years who were referred to the Taleghani Pediatric Hospital in Gorgan (Iran) during 2016. The subjects had a history of UTI and required antibiotic prophylaxis to prevent UTI. They were divided into two groups of co-trimoxazole and cephalexin. Data were analyzed using SPSS (version 18) and at significance level of 0.05.<br> <strong>Results:</strong> Recurrent UTI was observed in eight children (16.0%) taking cephalexin and in six children (12.0%) receiving co-trimoxazole (p=0.56). Urine culture examination revealed Escherichia coli as the causative agent of UTI in six cases (75 %) receiving cephalexin and in five cases (83.3%) receiving co-trimoxazole (p=0.70). It should be noted that unilateral moderate hydronephrosis was the most frequent anomaly (n=26) in the study groups.<br> <strong>Conclusion: </strong>According to the results of the present study, both cephalexin and co-trimoxazole have similar efficacy in the prevention of UTI among children.<br> &nbsp; Urinary tract infection, Children, Recurrent infection, Co-trimoxazole, Cephalexin 17 25 http://jcbr.goums.ac.ir/browse.php?a_code=A-10-207-4&slc_lang=en&sid=1 Jabar Parhiz 10031947532846003164 10031947532846003164 Yes Neonatal and Children's Health Research Center, Golestan University of Medical Sciences, Gorgan, Iran Sara Rahafard 10031947532846003165 10031947532846003165 No Neonatal and Children's Health Research Center, Golestan University of Medical Sciences, Gorgan, Iran Samaneh Sharifi 10031947532846003166 10031947532846003166 No Neonatal and Children's Health Research Center, Golestan University of Medical Sciences, Gorgan, Iran Farshid Kompani 10031947532846003167 10031947532846003167 No Neonatal and Children's Health Research Center, Golestan University of Medical Sciences, Gorgan, Iran