The article is devoted to the analysis of data concerning Ukrainians in Slovakia. The cultural and demographic criteria of the 2021 population census program became the information basis of the study.
 Despite the increase in the number of Ukrainians compared to the previous population census of 2011, the prospects for further growth in their number are rather doubtful. The Ukrainian autochthonous population is certainly being assimilated, but it is not known how the life trajectories of Ukrainian labor migrants will develop: whether they will move to Slovakia permanently, or return to Ukraine. The situation is similar with Ukrainian refugees after February 2022, who may move to live permanently, wait for the improvement of the situation in Ukraine to return, or consider Slovakia as an intermediate stage for emigration to another country.
 In general, the total number of Ukrainians and Ruthenians corresponds to the population census of 2001. That is, in the 20 years that passed between censuses, the presence of labor migration had absolutely no effect on the growth of the number of both Ukrainians and Ruthenians. In general, Ruthenians exert a destabilizing influence on Ukrainians. The analysis of the combinations "ethnicity", "other ethnicity" and "mother tongue" proves that Ukrainians and Ruthenians assimilate, quite a significant number of Ruthenians and Ukrainians keep their ethnic identity as a second one, instead, the main ethnicity and mother tongue are Slovak. The ethnic environment in which Ukrainians live can be characterized as quite homogeneous, and some of the largest ethnic minorities live compactly along the borders of their historical homelands.
 The homogeneity of the ethnic environment determines the homogeneity of the degree of multilingualism. Among the most numerous ethnic groups living in Slovakia, Ukrainians were the least likely to indicate the language of their ethnic group as their mother tongue. The presence of labor migration led to the fact that every tenth Ukrainian in the country indicated Russian as their mouther language.
 Compared to the most numerous ethnic groups in Slovakia, the age structure of Ukrainians has the highest share of people of working age, which allowed us to assume that a part of Ukrainians in Slovakia is represented by labor migrants. Additionally, it was found that the high share of Greek Catholics and Orthodox at the level of municipalities coincides with the compact settlement of Ukrainians and Ruthenians in the Pryashiv and Košice regions. Due to assimilation, the majority of Greek Catholics and Orthodox are Slovaks, not Ukrainians and Ruthenians, that is, ethnic and linguistic identity has been lost, but religious affiliation has been preserved.
 Keywords: Ukrainian diaspora, Ukrainians abroad, census of population, ethnicity, mother tongue, religious affiliation, index of ethnic diversity, index of linguistic diversity, ethnolinguistic correspondence.