The relatively rare neurocutaneous syndromes may produce neurological symptoms during childhood. After closure of the fontanelle, the radiological methods of choice are CT and MRT. The value of these two methods is demonstrated by twelve examples (eight neurofibromatoses, four tuberous scleroses). CT is superior to MRT in being able to show calcification; it is therefore the method of choice for tuberous sclerosis. On the other hand, MRT may show foci of neurofibromatosis; these can hardly be seen on CT. In order to show cerebral lesions in these two conditions, T2-weighted sequences are necessary.