Abstract Some quantitative properties of inflexional morphology of nouns in four Slavic languages (Czech, Russian, Slovak, and Slovene) are presented. We analyse the frequency behaviour of grammatical cases and the variability of noun word forms. The difference between a word form and its lemma is expressed by Levenshtein distance. Across the four languages under study, word forms more similar to the nominative form occur more often. We observe that the category of animacy has a decisive influence on the properties under study, with grammatical gender being another important factor.