Transnational migration challenges mental health services, as people coming from other geocultural worlds bring with them diverse ways of manifesting and coping with illness and suffering, and different therapeutic views. In recent years, there has been a dramatic rise in the number of foreigner patients in the mental health services of Prato (Italy). Linguistic difficulties and cultural misapprehensions urged psychiatrists and psychologists to develop a new methodological approach and to open their clinical settings to other professionals (anthropologists, linguists, interpreters, etc.). This article presents an analysis of such methodological developments, pointing out their organizational implications. Key words: clinical methodology, ethnopsychiatry, public service.