We have studied 4 children with tuberous sclerosis with one or more patches of depigmented scalp hair and in each case these were noticed by the parents at birth. In one patient the finding of a tuft of white hair preceded the appearance of white macules by many months. A tuft of white scalp hair is a useful new sign of tuberous sclerosis in the newborn and young child, and the hair should be examined as carefully as the skin when early 'organic' seizures are unexplained.