Thirty couples in which the female partners suffered from vaginismus were treated by sex therapy. Of the 30 couples, 80% had a positive outcome, these gains being sustained at three months follow up. The only prognostic indicator of importance was the extent to which couples were carrying out the homework assignments by the time of the third treatment session. The generally superior outcome of sex therapy for vaginismus by comparison with other female sexual dysfunctions is probably due to the very specific nature of the dysfunction in most cases and because couples with this problem have better general relationships, less psychopathology and higher motivation for treatment than other couples who enter sex therapy.