We report here a case of combined small cell carcinoma and sarcomatoid squamous cell carcinoma in the renal pelvis. A 61-year-old female presented with right flank discomfort, microhematuria and progressive renal dysfunction. Following diagnosis of right renal pelvic carcinoma, radical nephroureterectomy with lymph node dissection was performed through a midline incision. The tumor was pathologically diagnosed to be combined small cell carcinoma and sarcomatoid squamous cell carcinoma in the renal pelvis. The patient had no evidence of recurrence or metastasis, 16 months postoperatively. Small cell carcinoma or sarcomatoid squamous cell carcinoma of the renal pelvis is very rare. We believe this is the first such case to be reported in the world.