A case of a patient with multiple bilateral hamartomas of the kidneys is reported. The diagnosis of polycystic renal disease, suggested by the urographic studies had to be corrected after renal angiography. A well established diagnosis, basing on the striking angiographical findings was only possible, when we took notice of an adenoma sebaceum and other signs of the tuberous sclerosis complex. In cases of circumscribed unifocal lesions the antiographic findings may cause difficulties in the differential diagnosis between hamartoma and malignant hypernephroma. Therefore it is important to pay attention to other stigmata of tuberous sclerosis (Bourneville-Pringle's-syndrome). The differentiation between benign hamartoma and malignant hypernephroma may be possible by angiographic criteria alone, but many of the reported typical signs are of limited value.