Chicken egg-yolk antibodies are great, alternative to mammalian IgG, tool in research, diagnostics and therapy. Several advantages of IgY over conventional IgG are due to distinct structural and phylogenetic difference. They are successfully used in immunoassays such as Western Blotting, ELISA, immunoprecipi- tation, immunohistochemistry and others. Advanced IgY technology enables to treat some bacterial and viral diseases where conventional therapy fails. Production of egg-yolk antibodies, as a minimally invasive method, brings great benefit concerning animal welfare. Egg collection and further isolation of desired antibo- dies is fast, simple and cost-effective. Lack of information, insufficient experience or simply reluctance to new techniques is the main reason for moderate popularity of IgY. The objective of this paper is to provide information on applications and advantages of chicken IgY.