The concept of the unconscious fantasy -an organized configuration of unconscious ideas and images —has long played an important role in psychoanalytic theory. While most usually these fantasies have been discussed in terms of their pathogenic potential, there are also instances when the activation of particular unconscious fantasies can, under certain circumstances, have the opposite effect and reduce psycho-pathology. In the first part of this paper I describe a series of laboratory experiments that demonstrate under tightly controlled “double blind” conditions how the activation of two particular unconscious fantasies can serve an adaptation enhancing function. In the second part, I discuss how these same two fantasies can serve the same function when they are inadvertently activated in various types of psychotherapy. One of the fantasies that will be cited-termed the “symbiotic gratification fantasy” -is particularly apt to be activated in systematic de sensitization, client-centered therapy and meditation. The other-termed the “sanctioned oedipal gratification fantasy” -is most apt to be activated in Masters and Johnson type sex therapy, touching and other body contact therapies, behavior assertiveness training and encounter treatment.