We report a case of primary large cell neuroendocrine carcinoma of the renal pelvis, diagnosed in a 79-year-old man. The abdominal computed tomography showed a solid, vegetant lesion in the left renal pelvis, conditioning marked hydronephrosis. The patient underwent radical nephroureterectomy. The histological examination showed a large cell neuroendocrine carcinoma associated with a high-grade urothelial carcinoma, with local invasion (pT3). Large cell renal neuroendocrine carcinomas are rare tumors with an aggressive course and a bad prognosis. At present, only five cases were reported in literature.