Although insect pathogens are important naturally occurring biological control agents of insects, few exotic insect pathogens have been intentionally introduced into the United States. In part, this is because pathogens are more difficult to recognize and isolate in a foreign country than are parasitoids and predators and because pathogens have generally not been considered an integral part of the foreign exploration and introduction concept. Other reasons include taxonomic uncertainty and many undescribed species within many insect pathogen groups, lack of detailed information on biological characteristics such as host specificity and ecological interactions, little scientifically based information on what characteristics should be used to select the most appropriate exotic pathogen for introduction, and ambiguous regulatory requirements. These issues are discussed and future research needs are recommended.