We report the case of a 61-year-old man who was incidentally diagnosed with a left pelvic ectopic kidney with renal tumor. Computed tomography showed a hypervascular tumor at the posterior surface of the ectopic kidney with five arterial and two venous supply vessels. On preoperative examination, this patient had respiratory dysfunction. For these reasons, an open radical nephrectomy was performed. Histological examination revealed a clear cell renal cell carcinoma, pT1aN0M0, G1, and a Fuhrman nuclear grading system grade of G2. No evidence of disease was observed 15 months after surgery.