Of 75 patients with tuberous sclerosis seen at the Mayo Clinic in the years 1935 through 1967, 43 (58 per cent) had intracranial calcification or areas of sclerosis, or both, of the skull. There was no apparent consistent relationship between these roentgenographic manifestations of tuberous sclerosis and the presence of important signs of tuberous sclerosis, such as adenoma sebaceum, retinal phakoma, and seizure.