The 2011 population census recorded 4,290,612 residents of Croatia among which 584,947 or 13.7% were born abroad. Even though the most of them were born in Bosnia and Herzegovina (70% or 409,357) no research was conducted about this significant group of immigrants. This paper analyses the migration flows between Bosnia and Herzegovina and Croatia during the last 60 years, especially focusing on demographic data available from diverse secondary sources and data on migra-tion history and transnational activities obtained through empirical study “The Effects of Immigration from Bosnia and Herzegovina on the Sociodemographic Development of Croatian Urban Areas”. The survey was conducted in 2014 in Sesvete, district of City of Zagreb on a judgemental/purposive sample of 301 adult Croatian residents born in Bosnia and Herzegovina. Historical events (especially war) and economic developments had the influence on the number of immigrants as well as their motivation and decision to move from Bosnia and Hercegovina to Croatia. The data obtained through secondary sources and the results of conducted survey confirmed the shift in dominant migration patterns during three periods. First period, after the WWII until beginning of 1990s, indicated mostly labour migration where the migrations from Bosnia and Herzegovina to Croatia were mostly driven by economic underdevelopment of the country of origin and directed towards Croatian commercial and industrial centres. In the first half of 1990s the change of socio-political system (breakup of the former federal state) and the war in Croatia and Bosnia and Herzegovina induced significant forced migrations directed towards Croatia. After the end of the war and due to the consequences of armed conflict effecting the contemporary socioeconomic and political development of Bosnia and Herzegovina, a part of its citizens who were temporary settled in Croatia (as labour migrants or refugees) or elsewhere abroad, decided not to move back to Bosnia and Herzegovina but permanently stay in or move to Croatia. This was followed by the new period of migration driven (again) mostly by economic reasons complemented by general social situation and advanced unfavourable demographic processes in Bosnia and Hercegovina. These conditions stimulated the citizens of Bosnia and Hercegovina to migrate more frequently to other, economically more developed countries (Germany, Austria) effecting significantly the number of immigrants from Bosnia and Herzegovina in Croatia. The respondents included in empirical research are mostly Croats by ethnic affiliation (93.4%) and 99% of them have Croatian citizenship. In the highest proportion they migrated to Croatia during the 1990s. The results showed statistically significant correlation between the area of Bosnia and Herzegovina from where they moved to Croatia and the period of migration (the most numerous migrations were recorded from the area of the contemporary Republika Srpska). Three most frequent reasons of migration were war destruction (41.5%), economic reasons (33.2%) and family reasons (13%). Almost two thirds of respondents (63.1%) had no prior migration experience and more than 90% plan to stay permanently in Croatia. The study also confirmed significant social and transnational activities of immigrants. However, these respondents cannot be considered as the “typical migrants” since they largely share language, culture and tradition of receiving society which presents a favourable environment for their legal/political, socioeconomic and sociocultural integration.