The relationship between anxiety and cerebral blood flow (CBF) is of considerable clinical and research significance. Although a considerable amount of information is available on mechanisms through which anxiety may influence CBF, this topic has not received much attention in psychiatry. Earlier techniques for the measurement of CBF were cumbersome and invasive. With the advent of noninvasive techniques, study of CBF in psychiatric disorders, including anxiety, became easier, and a number of such studies have been conducted. In this article the literature on psychophysiological and clinical aspects of changes in CBF associated with anxiety is reviewed.