BACKGROUND The frequency of malignant tumors as a cause of death is increasing among kidney transplant patients. The aim of our study was to characterize kidney tumors occurring in the native kidneys of renal transplanted patients, and to determine their impact on recipient survival. METHODS We retrospectively analyzed the 43/3003 (1.43%) renal cell carcinomas (RCC) in the native kidneys of patients transplanted between 1973 and 2010. RESULTS During this period we diagnosed 293 posttransplant tumors, 14.6% of which were RCC. The male/female ratio was 2.1:1. The mean age of recipients at the time of tumor detection was 52.4 ± 12.1 years. The mean time from transplantation to diagnosis was 72.4 ± 61.6 months. RCC occurred on both sides in similar numbers. Tumors were multifocal in 8 cases. According to TNM staging, RCC was stage I in 38 cases. The histologic type was clear cell (n=27), papillary (n=13), chromophobe (n=2) or sarcomatoid (n=1). Radical nephrectomy was performed in 41 cases. Immunosuppressive management was converted to proliferation signal inhibitors in 27 patients (sirolimus n=19 or everolimus n=8). Fifteeen patients died at a mean survival time of 38.9 ± 62.4 months with 28 patients still alive at a mean follow-up 43.8 ± 35.6 months. Cumulative survival according to the Kaplan-Meier method was 79.2% at 1 year, 66.1% at 5 years, and 59.0% at 10 years. The patient survival rate was better among papillary than clear cell RCC (P=.038). CONCLUSIONS RCC was the second most frequent tumor among kidney transplanted patients at our center. The diagnosis established at an early stage in the majority of cases, leading to favorable patient survivals. A regular yearly abdominal ultrasound screening is suggested for early tumor diagnosis.