Primary sarcomas of the kidney are a rare entity and they account for 1 - 3 % of kidney malignancies, with the most common histological types being leiomyosarcoma and liposarcoma. Primary undifferentiated pleomorphic sarcoma of the kidney is a rare variant with a poor prognosis, with about 60 cases described in the literature. The case is presented of a 52-year-old female with a right renal tumour. It was surgically treated, with an immunohistochemistry-confirmed histological diagnosis of undifferentiated pleomorphic sarcoma of the giant cell variant.