Crossed-fused renal ectopia (CFRE) is a rare congenital disease in which one of the kidneys with its ureter crosses the midline and fuses with the contralateral kidney. The association of this malformation with the presence of primary renal cell carcinoma (RCC) is even more anecdotal; there are only a few cases reported in the literature. We describe the case of a 62 year-old man with CFRE associated with renal cell carcinoma, which was successfully removed by retroperitoneoscopy, after careful preoperative study of blood supply and anatomical features.