The available diagnostic and therapeutic possibilities allow to treat successfully all manifestations of von Hippel-Lindau disease. Adenocarcinomas of the kidneys, however, still present a serious therapeutic problem due to their mostly bilateral and multifocal occurrence. Evidence that patients after bilateral nephrectomy with subsequent dialysis or transplantation would have a longer survival time than patients whose kidneys had not been removed has not been provided as yet. Partial resection or enucleation of tumors may postpone the development of metastases but does not prevent tumor formation in the remaining parts of the kidneys. Considering the late appearance of metastases, though evidence only in one of our patients, we preferred not to remove the kidney and to introduce dialysis. The availability of sonography has put the kidney into the focus od attention in this disease. Not only does sonography allow to monitor regularly members of the affected families but also to screen for the disease at routine sonographic examination of the abdomen. (Fig. 7, Ref. 15.)