The author presented the introductory remarks including the brief historical review of the change in sexual concepts from Freud's thinking to the recent trends of human sexuality, and also described that psychosexual dysfunctions are recognized as distinct syndrome and impairment within the field of psychiatry, in which the adaptive psychophysiological changes neccessary for the progression of a person through a complete sexual response cycle are impaired in one or more phases. The author introduced definition and diagnostic criteria of impotence as follows. Impotence, more correct term as erectile dysfunction, defined as recurrent and persistent inhibition of sexual excitement during sexual activity, manifested either by the man's partial or complete failure to attain or maintain an erection until the complete failure to attain or maintain an erection until the completion of the sex act. Primary impotence; the patients who have never experienced in coitus with a woman, although they may attain good erections by masturbating and by spontaneous erections in other situations. Secondary impotence; the patients who functioned well for some time prior to the development of their erectile dysfunction. The prognosis is much better for secondary impotence than for primary impotence. Epidemiologically there are no significant differences among races or socioeconomic classes. The diagnosis is made in the light of clinical judgement that takes into account the focus, intensity, and duration of the sexual activity in which the patient emerges. The diagnosis is not made if the disturbance is caused exclusively by organic factors or is symptomatic of another clinical psychiatric syndrome. The causes of sexual impotence are presumed to be multiply determined by intrapsychic and interpersonal factors, lack of information, poor technique, and religious and cultural influences. Psychogenic impotence may be associated with a general loss of lobido but the essential role is a performance anxiety. The anticipated anxiety, shame and guilt feeling, and conflicts are important factors. Depending on Masters and Johnson's theory oriented to behavioral therapy, and modified by Kaplan, the basic strategies of sexual therapy are summarized as follows. 1. Brief, symptom-focused from of treatment, anxiety-relieving as target symptom occurring in sexual performance. 2. Restoration of confidence both in patient and in his sexual partner. 3. Inhibitory factors resolved. If neccessary, psychotherapeutic sessions performed. 4. Sexual tasks a) Non-demand pleasuring or sensate focus exercise. b) Dispelling the fear of failure, using squeeze method. c) Distracting obsessive thoughts and self-observer. d) Permission to be selfish and to use sexual fantasy. e) Coitus.