Although it has been generally accepted that psychological factors may influence the onset, complicate the course and may even play an etiological role in the production of psychosomatic diseases, psychodynamic mechanisms have been used by and large to explain the formation of psychosomatic symptoms. Recent clinical observations (Marty, deM’Uzan, Nemiah, Sifneos) suggest that certain broad personality characteristics such as an impoverished fantasy life and a constriction in emotional functioning which I call ‘alexithymic’, may be present in many patients suffering from a variety of psychosomatic diseases. It has been hypothesized that the existence of two different kinds of biological predispositions, one central and another peripheral, may account for the production of psychosomatic symptoms. Finally, it is concluded that for such patients dynamic psychotherapy is contra-indicated. A case example is presented.