Renal fibrosarcoma is a rare tumor, with only a few cases reported so far, and simultaneous occurrence of ipsilateral renal fibrosarcoma and renal pelvic carcinoma in a patient is extraordinarily rare. A 66-year-old man admitted to our hospital with right renal percutaneous nephrostomy and recurrent fever. And the patient underwent laparoendoscopic nephrectomy and partial ureterectomy for pyonephrotic nonfunctioning kidneys. Postoperative pathology showed fibrosarcoma of right kidney and carcinoma of the renal pelvis. This is the first case of simultaneous occurrence of ipsilateral renal fibrosarcoma and renal pelvic carcinoma in a patient. The diagnosis of fibrosarcoma is one of ultimate immunohistologic exclusion, because there are no specific immunologic markers for fibroblasts. Electron microscopy combined with light microscopy and IHC is helpful for the case of renal fibrosarcoma which is difficult to diagnose. Clinically, radical nephrectomy is the main strategy for primary localized renal fibrosarcoma. At present, it is still necessary to carry out basic biology research to better understand etiology and therapeutical strategy of renal fibrosarcoma.