Crossed renal ectopia is a rare congenital malformation. We report a case of renal cell carcinoma in a 51-year-old man with right-to-left crossed fused renal ectopia. The patient was treated with ultrasound-guided laparoscopic heminephrectomy. Postoperative three-dimensional computed tomography showed normal perfusion of the remaining part of the kidney, with good excretion of contrast from both units of the cross-fused kidney.