The study aimed at investigating the role of nominal gender in animal categorization in preschoolers. Given the regularities characterizing gender system, at both syntactical and morphological level, Italian language is suitable to address this issue. In three experiments, participants were asked to classify pictures of animals as male or female. Half stimuli had names of feminine gender and half of masculine gender. In Experiment 1, Italian speaking adults and preschoolers classified animals according to the nominal gender. This effect was not found with English speaking participants (Experiment 2) but confirmed with 3-, 4-, and 5-year-old Italian-speaking children (Experiment 3). These results showed an implicit knowledge of grammatical gender in preschoolers, suggesting that semantic processing may be modulated by linguistic information.