Renal transplantation has been advocated as the treatment of choice for end-stage renal disease. Immunosuppression increases the incidence of cancer and promotes the growth of neoplasm in solid-organ recipients. There have been few reports on the incidence of cancer from transplant registries. It is difficult to precisely ascertain the incidence of most tumors, and to compare their rates of occurrence with those in the general population, using data from small, single-center studies. Thus, we made a plan in this study to know the prevalence of genitourinary cancer development in Iranian renal transplant recipients. In the current study, we collected data from 5 kidney transplant centers in Iran between 1984 and 2008, to detect the incidence, type, and outcome of cancers after kidney transplantation. Only histologically confirmed tumors, which occurred after renal transplantation, were included in the analysis. Of the 5532 patients who underwent kidney transplantation, genitourinary tumors were detected in 18 (0.32%), 11 male and 7 female. Predominate genitourinary cancer was transitional cell carcinoma (TCC) of bladder (n=6); and followed by renal cell carcinoma (n=4), ovarian cancer (n=3), breast cancer (one male and one female), prostate cancer (n=1), seminoma (n=1) and uterine cancer (n=1). All RCC occurred in the native kidneys. Mean age of patients was 48 ± 10 (25-72) years and median time of diagnosis since transplantation was 45 (4-240) months, seven patients died during the follow up period. There was a male predominance in TCC of bladder and RCC (5:1 and 3:1, respectively). In conclusion, TCC of bladder was the most common genitourinary tumor following kidney transplantation and was predominancet in male.