The theoretical and empirical basis of commonly accepted propositions concerning the role of behaviour in the practice of behavioural psychotherapy for anxiety problems is considered. A number of problems are identified, and an alternative, more explicitly cognitive hypothesis is described. According to this cognitive account, there is both a close relationship and specific interactions between “threat cognitions” and “safety seeking behaviour”. For any individual, safety seeking behaviour arises out of, and is logically linked to, the perception of serious threat. Such behaviour may be anticipatory (avoidant) or consequent (escape). Because safety seeking behaviour is perceived to be preventative, and focused on especially negative consequences (e.g. death, illness, humiliation), spontaneous disconfirmation of threat is made particularly unlikely by such safety seeking behaviours. By preventing disconfirmation of threat-related cognitions, safety seeking behaviour may be a crucial factor in the maintenance of anxiety disorders. The implications of this view for the understanding and treatment of anxiety disorders are discussed.