Three cases of bilateral renal tumours are reported. A radical nephrectomy in the side with the larger tumour and a nephron-sparing surgery (partial nephrectomy or enucleo-resection) in kidney with smaller lesions was performed in two cases. A bilateral partial nephrectomy was performed in the last patient (tumours larger than 5 cm). Two of them performed a needle CT-guided biopsy before surgery, but full disagreement was found between pre and post-operative histological results. In addition, we outline that a second lesion was found intraoperatively in the case n. 3, without any radiological and sonographic finding. We stress the importance of a conservative surgery in case of bilateral neoplasms. Only surgery could assure a careful staging and histological diagnosis.