A 55-year-old male was referred to our hospital for left lower back pain. Computer tomography suggested a left ureteral stone and two left renal tumors at ventral and lateral sites. The ventral tumor measured 7 mm, and it showed intense early enhancement. On the other hand, the lateral tumor measured 22 mm, and it was enhanced weakly. We performed a single-stage robot-assisted partial nephrectomy, because he had chronic renal insufficiency and the two tumors appeared to be different types of renal cell carcinoma. Pathological examination revealed the ventral tumor was clear cell renal cell carcinoma, while the lateral tumor was papillary renal cell carcinoma. He is free of recurrence 1 year and 2 months after operation.