Urinary tract infections (UTIs) remain the most common infections diagnosed in outpatients and hospitalized patients. This study was designed to determine the patterns of antibiotic resistance and the prevalence of uropathogens causing UTIs in pediatric patients hospitalized between 1 January 2020 and 31 December 2022 at Teaching Hospital in Warsaw. The most frequent species isolated from urine samples wereE. coli(64.5%),Klebsiellaspp. (11.6%), andEnterococcusspp. (6.1%). UTIs caused byEnterobacterspp.,Enterococcusspp., andKlebsiellaspp. were significantly more common in children younger than three months of age than in children older than three months (p< 0.001). Trimethoprim and trimethoprim–sulfamethoxazole were the least active compounds againstEnterobacteraleswith the resistance ofE. coli,Klebsiellaspp.,P. mirabilis, andEnterobacterspp. in the range of 26.7/25.2%, 48.4/40.4%, 51.1/40.4%, and 15.8/13.2% respectively. Ampicillin was also found to have resistance rates forE. coliof 54.9% andP. mirabilisof 44.7%. Cefalexin and cefuroxime were highly active towardsEnterobacteralesexcept forKlebsiellaspp., in which the resistance level reached 40%. Regarding third- and fourth- generation cephalosporins, resistance inE. coliandP. mirabiliswas observed in approximately 2–10% of the isolates, but inKlebsiellaspp. andEnterobacterspp. ranged over 30%. The resistance ofEnterobacteralesto carbapenems, nitrofurantoin, and fosfomycin was below 1%. The quinolones resistance was very high forKlebsiellaspp. (31.1%) andP. mirabilis(29.8%) and three times lower forE. coli(11.9%),P. aeruginosa(9.3%),Enterobacterspp. (2.6%), andE. faecalis(4.6%). Resistance to multiple antibiotic classes was identified in 396Enterobacteralesstrains, 394 of which were multi-drug resistant (MDR) and 2 were extensive drug-resistant (XDR). In the case ofE. coli, 30% of isolates were MDR, with the proportion of strains having this exact resistance pattern similar in all of the analyzed years; noE. coliXDR strains were isolated. The number ofKlebsiellaspp. MDR strains was much higher in 2022 (60%) than in 2021 (47.5%). In the analyzed time, only one strain ofK. pneumoniaXDR, producing New Delhi metallo-β-lactamase, was isolated. Monitoring infection trends is essential to improve control and limit the rise of bacterial resistance.