Tumours of the kidney with sarcomatoid elements are uncommon. The radiological findings in 11 patients with such lesions are presented. It is important to separate pure sarcomas from lesions with sarcomatous and carcinomatous elements since they have different radiological appearances and prognosis. These tumours often show calcification on radiographs and on angiography appear predominantly avascular with a blood supply from capsular vessels. Because of their rarity and the overlap of radiographic findings with more common tumours the diagnosis cannot be made by current imaging methods alone.