The graduation thesis discusses the course of events in the real estate market in the Karst region, after Slovenia's accession to the European Union. We analyzed the advertised prices of residential houses in four Slovenian municipalities (municipality of Sežana, municipality of Divača, municipality of Hrpelje-Kozina, municipality of Komen) and six Italian municipalities (municipality of Trieste, municipality of Devin-Nabrežina, municipality of Repentabor, municipality of Milje, municipality of Zgonik) in the period from December 2012 to May 2013. The results of the analysis are based on the data on advertised houses from gathered ads and are accessible in reports and records. It was established that the average advertised price of residential houses per square meter for the whole Slovenian territory is about 1100 euros lower than the average advertised price of residential houses per square meter for the whole Italian territory. Therefore, residential buildings on the discussed Slovenian territory are an interesting purchase at least for a certain group of Italian citizens. We also have to take into account other factors such as natural resources, peace and unspoiled nature and historic connections of these two areas. The increasing interest for properties in the administrative unit of Sežana is also a result of a sales comparative analysis in the three neighbouring administrative units. We have established a greater increase in the average prices of residential houses and land in the administrative unit of Sežana as well as in the administrative unit of Nova Gorica and Ajdovščina.