Approximately 43% of the larval bagworm population in the Athens, Ga., area were killed by naturally occurring biotic factors during the period July through Sept., 1970. About 71% were killed in 1971 and 66% in 1972. Nineteen insect species including parasitoids, hyperparasites, and scavengers were reared from dead bagworm larvae and pupae. The bagworm is a new host record for 9 of these insects. Bagworm pathogens included bacilliform bacteria, a polyhedrosis virus, and fungi belonging to the generaAspergillus, Penicillium, Geotrichum, Paecilomyces, Hirsutella, Beauveria, Cordyceps, Scopulariopsis, andPestalotia.An inverse relationship existed between the levels of fungal disease and parasitism in larval populations. During 1971 a high level of fungal disease (51%) and a low level of parasitism (10%) were recorded. In 1970 and 1972, high levels of parasitism (29% and 46%, respectively) and low levels of fungal disease (13% and 17%, respectively) were recorded. It appears that fungi contributed most heavily to bagworm mortality during wet periods and that insect parasitoids were the predominant mortality factor during dry periods.