This paper aims at analyzing the socio-demographic structure of Venezia Giulia and Macedonia, focusing on the cities of Trieste and Thessaloniki and their surroundings in the period between the end of the 19th century and the middle of the twentieth century. The two cited examples present in fact a series of similarities, such as the strongly hierarchical connotation of the triple ethnic stratification common to both realities, characterized by the presence at the upper level of an administrative and military «caste» (in first case the Germans, in the second the Turks); the intermediate level was instead reserved for the dominant «historical» nationality (Italian in the north, Greek in the south), dedicated above all to commercial activities, while the lower level was occupied by predominantly peasant Slavic masses (Slovenian in Venezia Giulia, Bulgarian/Macedonian in Macedonia). Finally, the importance of local Jewish communities should not be underestimated.