The avian egg is designed to support the autonomous development of the chick embryo in the outside environment. It initially contains all the nutrients required for embryonic growth and provides efficient physical and immune protections primarily via the calcified eggshell and the numerous antimicrobial proteins and peptides. The antimicrobial content of eggs has been shaped during evolution to cope with the microbial pressure and potential contaminations. These antimicrobials are present within all parts of the egg, although they are mostly abundant and active in the egg white and in the perivitelline layer. Egg antimicrobial molecules show high structural and functional diversity, displaying bactericidal or bacteriostatic activities via different but complementary mechanisms (e.g. interaction with bacterial cells which further triggers permeabilization and bacterial death, decrease in the bioavailability of nutrients required for microbial growth, inhibition of microbial proteases involved in virulence). Interestingly, some of these antimicrobials lack orthologs in mammals and are specifically deposited in eggs by the hen during egg formation, which suggests that they have a specific role in the innate immune protection of the avian egg, or even other biological functions related to avian reproduction. The presentation will mainly focus on a selected panel of relevant egg antimicrobial proteins and peptides with a particular emphasis on their structural and phylogenetic features.