The paper builds on the premise of the constructivist theory, according to which ethnicity and ethnic identities are not in straightforward connection with the social groups (Brubaker). Viewed from the perspective of the events taking place in the 1990s, the research differentiates between two basic types of multiethnic areas in Croatia: (a) the areas in which the conflicts escalated to the level of disintegration of different forms of community life – the “conflict areas”; and (b) the areas in which radical conflicts were avoided and the multiethnic cohabitation was to a large extent maintained – the “peace areas”. A research survey, whose results are presented in this paper, was conducted during October 2008 in the local communities matching the description of the “conflict areas”, these being Gospić, Plaški and Pakrac, and of the “peace areas”, these being Rovinj, Vrbovsko and Daruvar. Apart from this, some qualitative methods of data collecting have been used. The intention underlying this paper is to provide an answer to several essential questions concerning the processes of identification and maintenance of group boundaries and ethnic distance in multiethnic areas. On the basis of previous research, it may be assumed that these processes are affected by events occurring in the recent and more distant past, as well as by the interplay between the existing system factors and the social actors of peace or conflict. However, the results of the study in a certain way support the constructivist hypothesis on instrumentalization of ethnicity in constructing group boundaries and thereby in the dynamics of ethnic mobilization, ethnic conflict and ethnic peace.