The introduction of sex therapy two decades ago was accompanied by largely uncritical enthusiasm, with the result that too few careful evaluative studies were conducted. Those that were indicated that a weekly or twice weekly schedule of treatment sessions was best and that treatment by individual therapists was as effective as co-therapy. Some of the major prognostic factors and the long-term results of sex therapy have now been elucidated. Low sexual desire has emerged as a problem for which our now traditional methods of treatment are often inadequate and new therapeutic approaches are required. Current efforts to explore the beliefs and cognitive processes associated with erectile dysfunction are proving rewarding and are likely to enrich therapeutic interventions in the future. Attention should now be paid to the beliefs and cognitions associated with other sexual dysfunctions, both male and female. © 1991, British Association for Behavioural and Cognitive Psychotherapies. All rights reserved.