The author begins by pointing out that myths have always been powerful vehicles for the projection of ubiquitous unconscious fantasies. Having noted the importance of certain male protagonists of the Greek myths in Freud's theories, she observes that their female counterparts exert an equal fascination and suggests that the Medea myth as recounted by Euripides can be invoked to elucidate a central unconscious fantasy found to underlie the psychogenic frigidity and sterility of several of her female patients. The manifestation of this ‘Medea fantasy’ is illustrated by a clinical account in which a dream is analysed. The author next summarises the Medea story as told by Euripides and attempts a psychoanalytic interpretation of it. She draws attention to features of the ‘unconscious truth’ inherent in the myth that were shared by all the members of her group of patients. A case history then shows how the progressive understanding and working through of the Medea fantasy led to a change in the analysand's experience of femininity and enabled her to have children. It is postulated that both early infantile sexual fantasies and repressed memories of early objectrelations traumas such as maternal depression combine with ubiquitous bodily fantasies to produce the unconscious Medea fantasy.