Microplitis rufiventrisKokujev (Hymenoptera: Braconidae) was imported from Cairo, Egypt, into the United States, where it developed successfully in the corn earworm,Heliothis zea(Boddie); the soybean looper,Pseudoplusia includensWalker; the beet armyworm,Spodoptera exiguaHübner; the fall armyworm,Spodoptera frugiperda(J. E. Smith); the cabbage looper,Trichoplusia niHübner; the black cutworm,Agrotis ipsilon(Hufnagel); and the tobacco budworm,Heliothis virescens(F.). Mean developmental time from oviposition to adult was 13.6–15.6 d at 28°C depending on host species.P. includensyielded the highest percentage of female progeny; however,H. zeaandS. frugiperdawere preferred hosts in laboratory tests utilizing these three hosts. The parasitoid successfully searched in field cages forH. zea, P. includens, andS. frugiperdafeeding on soybeans. Incidence of parasitism reached 95% ofS. frugiperdaandH. zeain field cages.