The monograph on immigrants' health recently published by Epidemiologia & Prevenzione provides an updated contribution to this subject by the Italian Network of Longitudinal Metropolitan Studies. This paper suggests methodological and thematic aspects that should be addressed by future studies in order to provide the knowledge relevant to social and health policies: networking with researchers and with the subjects dealing in various ways with immigration as well as the preparation of a communication plan aimed at the community and at decision makers are the methodological aspects on which the possibility of studies generating actions depends. Among the objects of investigation the health of the second generations, the study of drug prescriptions and of the access to Emergency Room as well as the evaluation of the interventions implemented by each municipality seem the most relevant. The need of a timely and periodic monitoring of the health outcomes is also underlined and the possibility of a study on the health of migrants during their migrant journey is proposed.