Recent opinions on the pathology, diagnostic methods and treatment of cystic nephroma are presented. This will be illustrated by a review of 10 patients with known cystic nephroma, operated and followed by our department. There is clear evidence that cystic nephroma is a benign lesion of the kidney, although the existence of two types of lesions has not definitely been excluded. Sonography and computerized tomography are effective methods for the identification of the lesions preoperatively. In doing so a conservative surgical approach is the treatment of choice.