The relevance of hypnosis to the treatment of sexual assault derives from two sources: the fact that hypnotic phenomena are mobilized spontaneously as defenses during assault, becoming part of the syndrome of posttraumatic stress disorder (PTSD) and the usefulness of formal hypnosis in treating PTSD. The role of dissociative defenses during and after traumatic experiences is reviewed; an analogy between the major elements of formally-induced hypnosis--absorption, dissociation, and suggestibility, and the major elements of PTSD--is drawn. Special problems relevant to sexual assault in childhood are discussed, including extreme self-blame and a profound sense of personality fragmentation. Uses of hypnosis in the treatment of sexual assault victims are reviewed, with an emphasis on helping such patients restructure their memories of the experience, both by reviewing them with greater control over their physical sense of comfort and safety and by balancing painful memories with recognition of their efforts to protect themselves or someone else who was endangered. The use of a split-screen technique in hypnosis is described with a clinical example. Special considerations in such treatment, including the traumatic transference and forensic complications of such psychotherapeutic work, are enumerated.