Immunosuppressive drugs are one of the important risk factors of bacterial infections, especially urinary tract infections (UTIs) in the renal transplant recipients (RTR). The aim of this study was to be determine UTI prevalence and its relation with diabetes mellitus, adult polycystic kidney disease (APCKD) and raising of serum creatinine among RTR during long–term follow–up. One hundred RTR were followed from May 1993 to May 2000 in No.1 specialty clinic of Tabriz University of Medical Sciences. These patients were followed for any complication of UTI after renal transplantation and after being discharged from hospital. The data were analyzed using SPSS software. Out of total patients enrolled in the study, thirty eight percent had one or more than one episodes of UTI in the first 6 months and 44 episodes after first 6 months of renal transplantation. The other 22.5% of patients with UTI were found asymptomatic. The most prevalent infectious agent was E. Coli in first 6 months with prevalence of 44% and 37.7 % in next 6.5 years. The cause of renal failure was APCKD in 4 patients and diabetes mellitus in 6 patients. Incidence of UTI in these two groups was not higher than other patients (p = 0.55, p= o.88). Statistical analysis showed that UTI does not have any relation to the gender (p=0.138), and also the blood level of creatinine determined at the time f study, did not correlate with UTI. Result of this study showed that UTI is prevalent among transplanted patients. For decreasing the side effect of immunosuppressive drugs, specially UTI, it is recommended that continuous follow–up of these patients is necessary, and this follow–up must include urine culture, specially among patients with history of positive cultures.