In December 1918, Hungary ceded 21,000 square kilometers to what was soon to become the Serbo-Croatian-Slovenian Monarchy. According to 1910 census data, of the total 577,000 ethnic Hungarian population on the ceded territory, one-fifth came under the jurisdiction of Croatia, approximately one-twentieth came under the jurisdiction of Slovenia, and the rest became citizens of Serbia in the region that was to become the autonomous province of Vojvodina. According to 1991 census data, the Hungarian-speaking minority decreased by 200,000 (over one-third), and its proportion of the population also changed: currently, only 6 percent live in independent Croatia and 2 percent in independent Slovenia. The population of Hungarians in Croatia decreased by four-fifths, and that of Slovenia decreased by two-thirds. Already between 1980 and 1990, the decrease in the Hungarian minority population exceeded 10 percent in both republics. Despite the differences in the condition of the Hungarian community in Croatia and Slovenia, their total assimilation can be averted only if serious measures are taken. An analysis of the political, economic, demographic, cultural and other factors contributing to the population decline since the post-world war peace treaties is beyond the scope of this article. I would merely like to point out the general demographic trends and indicate that, according to estimates, the Hungarian population is 1.5 times larger (22,400 in Croatia and 8,500 in Slovenia) than the figure revealed by census data.