The importance of the general climate of a psychiatric clinic for the treatment of psychiatric patients is a wel known and widely accepted fact. However, the systematic and methodological manipulation of those factors of the social environment that have a therapeutic effect, which the authors call sociotherapy, remains a point for discussion. This article focuses on some theoretical and practical implications of sociotherapy. After a short historical overview of milieutherapy, the authors try to formulate an adequate theoretical frame-work: emphasizing the concept of adaptation, Ego-strengthening is seen as a goal and techniques that should be applied to reach this goal are discussed; the social structure of the clinic has also to be analysed, especially communication and the sharing of power. In addition some practical problems are discussed. The authors consider socio-therapy as a part of the whole therapeutic approach to the patient; the therapeutic techniques and social structuring must depend on the characteristics of the patient-group; some problems of the staff-members are also discussed. The authors stress the importance of the relations with the community for a succesful sociotherapy.