Objective - To describe the cooperation in mental health that, since ten years, the Institute for Pharmacological Research ≪Mario Negri≫, Milan, is carrying out in Latin America. The project has developed along three main lines: the training of the mental health services personnel, the promotion of an epidemiological approach to the mental health care, and the assistance to the local health authorities in the field of mental health policy. Results - The most relevant goals of the project have been the Caracas Conference on the Latin American psychiatric hospitals and the constitution of an European Consortium for the technical cooperation with Latin America in mental health. Most of the activities have been done in cooperation with WHO regional office (Organización Panamericana de la Salud). Furthemore the paper outlines the main results of two epidemiologic studies carried out in Central America. Conclusions - The psychiatric hospitals phasing out, the setting up of mental health community-based services and the close cooperation between psychiatric services and primary health care services are the main objectives of a project of cooperation in mental health; training and epidemiological research must be the methodological tools of this type of cooperation.