The issue of social inequalities is analyzed as a global issue of modernity.Social inequalities are emphasized to differ by natural historical dimension; they are repro-duced in rather stable forms as a reflection of political, economic, cultural normative structureof a society being thus immanent for all phases of societal historical development. Inequali-ties represent specific form of social differentiation, pre-determining differences in vital condi-tions for individuals and social groups mediating for them different chances to satisfy actualdemands and interests. Character, causes, depth, and specifics of social inequalities in post-Soviet Russia are discussed on the bases of all-Russia surveys between 2003 and 2013;main indices and social economic factors of the inequalities are elicited. Thinking patternsof Russians are analyzed regarding just and unjust, legitimate and illegitimate, as well as158excessive inequalities. Destabilizing role of illegitimate inequalities is stressed as a barrier toRussia’s progressive development.