Hypochondriasis and other syndromes in which health anxiety is prominent are frequently seen in clinical practice and often pose problems of management. In contrast with other anxiety problems, the conceptualization and treatment of health anxiety has developed very little in recent years. Behavioural approaches to treatment have only recently been applied. In the present paper, current theoretical models are critically evaluated and a cognitive-behavioural approach is proposed to account for the development and maintenance of hypochondriacal problems. Principles of cognitive-behavioural treatment based on this approach are outlined, together with some suggestions for research.