This article discusses the concept of modern prejudice and in particular the reactions showed by autochthonous people in presence of a large number of immigrants coming from Africa and East Europe. Through a sociological and a psycho-sociological perspective, modern prejudice is defined by examining differences between traditional racism and new forms of discrimination. The theoretical contributions of authors such as Balibar and Wallerstein, Pettigrew and Meertens, Dovidio and Gaertner, which identified the typical dimensions defining modern prejudice, are examined. The discussion then considers methodological and technical difficulties connected with the need to operationalise such attitudes. Due to the widespread presence of social desirability bias, it is argued that it would be useful to adopt an approach using quantitative and qualitative data collection tools. A critical review of recent research concerning Italians' and other Europeans' attitudes toward immigrants shows the theoretical and methodological complexity underlying the concept of modern prejudice.