We studied the relation between primitive reflexes (glabellar, snout and palmomental) and MRI findings, cerebral blood flow and mental function in 68 normal aged volunteers. One or more of the three primitive reflexes was elicited in 50% of all subjects. The subjects who had the incidental cerebral lesions showed a significantly higher incidence of the primitive reflexes than those without them. However, there was no difference in mean regional cerebral blood flow (rCBF), brain atrophy and intellectual ability between the subjects with primitive reflexes and those without. The primitive reflexes appear in a significant proportion and these reflexes have a significant relationship with incidental cerebral lesions in normal elderly.