Renal transplantation is the main treatment for end-stage kidney disease. Transplantation reduces the mortality rate and increases life quality in this population but cancer in allograft kidney is a major problem. Here, we report a 39-year male who had renal transplantation 10 years ago. On routine follow-up, radiologic imaging revealed a 32 mm mass in the allograft kidney. After partial nephrectomy, histopathologic examination revealed mucinous tubular and spindle cell variant of renal cell carcinoma(MTSCC). To our best knowledge, this is the first case in the literature that underwent partial nephrectomy in the transplanted kidney and was diagnosed with MTSCC. Key Words: Renal mass, Mucinous tubular and spindle cell tumor, Kidney transplantation.