The major purpose of this article is to research the determinants of hard-to fill job vacancies from a theoretical perspective and rank the EU member states by their labour market conditions taking into account the data for 2021. The labour market conditions are represented by the indicators (percentage of the unemployed in the working age population; employment level, %; annual AVG long-term unemployed, % (percentage of unemployment); annual AVG long-term unemployed, % (percentage of population in the labour force) that not only reflect the situation in the labour market, but also have a direct connection with hard-to-fill job vacancies. The novelty of the research lies in the nature of the analysis: the EU labour market is researched by connecting the relevant indicators with hard-to-fill job vacancies (to the best of our knowledge, only a few studies on this issue have been conducted thus far). The research is based on the following methods: literature analysis, statistical data analysis, the Promethee method, the entropy method. The empirical research revealed that the most favourable labour market conditions are observed in the Netherlands, followed by Denmark and the Czech Republic, while Greece and Italy are at the end of the ranking. The examples of the best practice suggest that the EU members states at the end of the ranking may consider adopting the Danish flexicurity model, the model of social dialogue of the Netherlands or the Czech Republic's concentration on labour and social policies that help to reduce the impact of the population ageing/demographic developments and offer flexible work conditions relevant to the post pandemic period (remote work, work from home, etc.)..