Quality psychiatric services demand that clinician and patient communicate effectively. Many migrant patients do not have sufficient command of the languages of the host culture necessary to communicate well, and rarely are there enough professionals who speak the language of the patient in question present in the treatment center. In addition, intercultural communication requires much more than simple literal translation; it involves the complex process of making sense out of the non-verbal communication, emotional expression, and metaphors. Difficulties in intercultural communication can seriously detract from the quality of the therapeutic relationship, key to effective diagnosis and treatment. The intercultural mediator represents a new profession whose primary responsibility is to facilitate the development of the therapeutic relationship by bridging the communication and cultural gap between the autochthonous psychiatrist and culturally different patient. The presence of a third party can be unnerving to the clinician who is not accustomed to giving up control over the session as occurs with the cultural mediator who is the only one who understands first hand what is said by each party. Intercultural mediation in psychiatry is highly demanding, and requires considerable flexibility as well as a sound understanding of the psychiatric interview and the therapeutic alliance. Effective use of an intercultural mediator is difficult, and requires the application of a number key processes, which, in combination with a well-trained intercultural mediator can result in highly effective intercultural psychiatric diagnosis and treatment.