Although the epidemiology of nosocomial urinary tract infections (NUTIs) is well-described in the adult population, there is little information on children. We therefore reviewed all our patients with NUTIs, to determine their age, underlying diagnoses, microorganisms involved, use of catheters and secondary bacteremias. During a 2-year period at our institution, NUTIs accounted for 10% of all nosocomial infections (0.8 infections/100 admissions). Of 44,948 patients admitted during this period 0.7% (n = 318) acquired 351 episodes of NUTI. The patient ages ranged from 5 days to 21 years. The highest rates of NUTIs per ward (NUTI/100 admissions or transfers to the ward) were seen in the neonatal surgery (4.8), hematology/oncology (2.7), infant neurosurgery (2.1) and neonatal intensive care units (1.9). The most common organisms isolated were Escherichia coli (26%), Enterococcus sp. (15%), Pseudomonas sp. (13%), Klebsiella sp. (10%) and coagulase-negative Staphylococcus (9%). Catheterrelated infections accounted for 48% of all the NUTIs. Secondary bacteremia occurred rarely, with an incidence of 2.9% (n = 7). We conclude that NUTIs represent an important proportion (10%) of nosocomial infections in our population of hospitalized children, but secondary bacteremia is uncommon.