AbstractInsects have evolved many mechanisms that reduce their potential for serving as hosts for entomophagous species. Some of these mechanisms involve escape, mimicry, and repellancy, which are effective defense mechanisms against both predators and parasitoids. But, insects have a second line of defense against parasitoids and parasites. These may include repellancy and a cuticular barrier to invasion but they include several internal defenses that are collectively referred to as immune mechanisms.The current understanding of insect immunity is reviewed as background to examining the ways in which insect parasitoids have evolved to successfully handle the immune system of the host. The various means that parasitoids utilize to handle the insect immune systems have been divided into five approaches. These five approaches are described and current knowledge of the mechanisms used by parasitoids to deal with the immune system of their host is explored.