The ovary and oviduct of the hen are susceptible to various pathogenic microorganisms, and infections in these organs may not only contaminate the eggs, but also disorder the egg formation. The immune function of the ovary and oviduct is essential to protect these tissues from infection as well as for the production of hygienic eggs. This paper reviews recent studies on the host defence system in the reproductive organs with reference to their innate immune functions, with emphasis on the important role of Toll-like receptors and avian beta-defensins in this defence system.