Urinary tract infections (UTIs) are the most common infectious complication following renal transplantation. Previous studies uniformly report that renal transplant recipients develop UTIs more often than the general population, but widely differ on how frequently UTIs occur after transplantation. These studies also disagree on the risk factors associated with developing post-transplant UTIs, as well as the effect that UTIs may have on graft outcomes and patient mortality. We performed a retrospective cohort study including all the adult patients who received a renal transplant at two US transplant centers from January 1996 to December 2002 (500 patients). Two hundred and thirteen (43%) patients developed one or more post-transplant UTIs over a mean follow-up period of 42 months. Significant risk factors for post-transplant UTIs were advanced age, female gender, reflux kidney disease, use of azathioprine and cadaveric donor. UTIs did not increase risk for renal graft loss, but were associated with increased mortality (3.5 odds ratio, 95% confidence interval 1.68-7.23). We conclude UTIs may be associated with an increased mortality risk in renal transplant recipients. Prevention of UTIs in high-risk renal transplant patients or those with recurrent UTIs may possibly decrease post-transplant mortality.