Collecting duct carcinoma is a distinct entity among renal cell carcinoma, which is characterized by an aggressive behavior. Sarcomatoid variants of this tumor are rarely described. We report the case of a 62-year-old woman who presented with a left kidney tumor. A radical nephrectomy was performed. The tumor was firm with a white appearance, located in the medulla with infiltrating margins. Pathological examination showed a biphasic tumor with carcinomatous areas consisting of a collecting-duct carcinoma and sarcomatous areas with malignant fibrous histiocytoma-like appearance. Immunohistochemical studies confirmed the diagnosis of sarcomatoid collecting-duct carcinoma. The patient died 8 months after the diagnosis.