Along with three traditional inflectional categories of Modern Russian numerals and adjectives (gender, number, and case), a fourth category is proposed: animacy, relevant in the accusative case for all Russian adjectives and some Russian numerals (ODIN ‘one’, DVA ‘two’, OBA ‘both’, TRI ‘three’, čETYRE ‘four’, and all collective numerals of the type DVOE ‘two’, TROE ‘three’, …) Thus, in Ja vižu krasivogo junošu ‘I see a handsome youth’, krasivogo ‘handsome’ is represented as KRASIVYJ(masc, sg, an, acc), as opposed to krasivyj ‘beautiful’ in Ja vižu krasivyj dom ‘I see a beautiful house’: KRASIVYJ(masc, sg, inan, acc). Two methodological principles are formulated: THE PRINCIPLE OF EXTERNAL AUTONOMY OF CASE FORMS (two different nominal word-forms cannot represent the same case if they are distributed according to external context), and THE PRINCIPLE OF SIMPLEST RESTRICTION (the subset of a paradigm for which a category is judged to be relevant should be specified by only one inflectional category). Seven facts about Russian morphology and syntax are cited to support the introduction of animacy for numerals and adjectives. Two further problems are discussed: the relationship between animacy and other inflectional categories of Adj and Num in Russian, and the relevance of animacy for Adj and Num lexemes.