A 50-year-old male underwent a nephron-sparing surgery for a small renal incidentaloma, which was atypical for renal cell carcinoma in diagnostic images. The tumor was pathologically diagnosed as renal tubulopapillary adenoma. Three years later, another tumor was pointed out in the ipsilateral kidney, and he underwent a radical nephrectomy. The latter was diagnosed as clear cell carcinoma. We report this very rare case of unilateral and metachronous occurrence of renal tubulopapillary adenoma and renal cell carcinoma.