The author analyses the effects of transition and war on the formation of some segments of national identity among Croats and Serbs. The basis for the analysis was an empirical survey conducted in Western and Eastern Slavonia. The analysis included three groups of war migrants and victims of war – indigenous Croats, indigenous Serbs and immigrants. The survey was conducted between September and December 2004, in villages and towns of Western and Eastern Slavonia. It used a survey questionnaire with 48 closed-type questions. The survey took account of the following variables among respondents: sociospatial status, age, gender and level of education. The analysed variable: respondents’ sociospatial status, proved to be in correlation with the perception of some segments of national identity among Croats and Serbs. The results of the survey showed differences in the opinions and evaluations of respondents from Western and Eastern Slavonia. Indigenous Croats, more than indigenous Serbs, stressed the meaning and importance of religion (Catholicism) in national identity. Indigenous Croats were more exclusive than indigenous Serbs as to the possibilities of full participation of former Communists in the Croat and Serb national communities. The responses of immigrants were more radical and exclusive in comparison with indigenous persons, and in this regard responses of immigrants in Western Slavonia (mostly ethnic Croats) were more radical than responses of immigrants in Eastern Slavonia (mostly ethnic Serbs). Although they were somewhat laced with exclusive opinions on the possibilities of including various subidentities in the national identities of Croats and Serbs, the respondents’ answers indicate that in the post-war period, in former war areas, tolerance is also quite present, more noticeably within one’s own group than towards the other nationality.