Post-communism has not changed the way post-Soviet states use identity categories on the census. All of them continue to count their population according to an ethnonational criteria. The principle of self-determination, according to which a state is based on the historic right of a so-called “titular” nationality, has consolidated the hegemony of the nationality mindset. A primordialist vision of historical science as the ultimate means to gauge the authenticity of national claims remains prevalent in academic and political discourse. During post-Soviet censuses, the most important claims seeking to separate a group from a titular nationality were rejected by Russian, Ukrainian, and Tatar elites. These censuses have also shown an important decrease of Russian populations outside of Russia, due to an “acceleration decolonisation” in the South and an “identity reidentification” in the West, as in Ukraine. The Russian Census was open to public debates, a civic improvement that is called into question by the resurgence of authoritarianism in Russia.