Urinary tract infection (UTI) is one of the most common infectious complications among renal transplant patients. Trimethoprim-sulfamethoxazole (TMP-SMX) is routinely used as first-line prophylaxis against Pneumocystis pneumonia (PCP) and other opportunistic infections including UTI. Aerosolized pentamidine is an alternate agent used for PCP prophylaxis, however it does not provide coverage against uropathogens. This is a retrospective study of 81 renal transplant recipients who received TMP-SMX or aerosolized pentamidine for PCP prophylaxis at our center over one year. Survival analysis demonstrated increased cumulative incidence of UTI among patients receiving pentamidine for PCP prophylaxis compared to those receiving TMP-SMX (Log-rank test p<0.001). Univariate and multivariate Cox proportional hazard regression model showed pentamidine prophylaxis (HR 3.740; 95% CI 1.745-8.016; p=0.001) and female sex (HR 4.025; 95% CI 1.770-9.154; p=0.001) to independently increase UTI risk. Age, induction agent, graft type, diabetes, and delayed graft function (DGF) were not associated with increased risk. This study concludes that the use of pentamidine for PCP prophylaxis compared to TMP-SMX is associated with increased risk of UTI. Secondary UTI prophylaxis may be considered for patients who are unable to tolerate TMP-SMX and who have other risk factors for UTI, however the efficacy of this has not been studied.This article is protected by copyright. All rights reserved.