BACKGROUND Urinary tract infections (UTIs) are most common infections in renal transplant recipients and are considered a potential risk factor for poorer graft outcomes. OBJECTIVE To evaluate incidence, clinical manifestations, microbiology, risk factors for UTIs, and the influence of UTIs on long-term renal graft function. METHODS We analyzed urine cultures with reference to clinical data of patients who received a renal transplantation from January to December 2009 with a 12-month follow-up. RESULTS The 1170 urine cultures were correlated with clinical data from 89 renal transplant recipients, including 58.4% males and on overall mean age of 48±14 years. The 151 episodes in 49 patients consisted of asymptomatic bacteriuria (65%, n=98); lower UTIs (13%, n=19); and upper UTIs (22%, n=34), as well as five cases of bacteremia. Nearly 48% of UTIs were diagnosed during the first month posttransplantation. The most frequently isolated uropathogens were Enterococcus faecium (33%, n=24) and Escherichia coli (31%, n=23). Beginning from the second month, most frequently found bacterium in urine cultures was E coli (65% n=51). Risk factors for posttransplant UTIs were female gender and a history of an acute rejection episode and/or a cytomegalovirus (CMV) infection. All patients with vesicoureteral reflux of strictures at the ureterovesical junction suffered recurrent UTIs (n=7). The evolution of renal graft function did not differ significantly between patients with versus without UTIs. CONCLUSIONS UTIs a frequent problem after kidney transplantation most commonly exist as asymptomatic bacteriuria. E coli and E faecium are ther predominant pathogens. Exposure to intensified immunosuppression due to acute rejection episodes or CMV infections represents a risk factor for UTIs. Vesicoureteral reflux or strictures at the ureterovesical junction are risk factors for recurrent UTIs. UTIs did not impair 1-year graft function.