The soybean aphid, Aphis glycines Matsumura (Homoptera: Aphididae) has become a serious problem in the US since its first landing in 2000. In Asia, outbreak of soybean aphid in a large scale is rare, and natural enemies play an important role in keeping the soybean aphid under the economic injury level. The commonly-found natural enemies include parasitic wasps, parasitoid flies, coccinellid beetles and entomopathogens. In this study, we investigated the host range of several exotic aphid parasitoids including 4 parasitic wasps, Aphidius sp., Lipolexis gracilis Forster, Trioxys spp. (Hymenoptera: Braconidae: Aphidiinae), and 1 parasitoid fly, Leucopis sp. (Diptera: Chamaemyidae) which were introduced from Asia (China, Japan and South Korea) in 2001-2003. A dozen of aphid species were used for the test. These aphids are taxonomically close to A. glycines and belonged to the tribes Aphidini and Macrosiphini (Homoptera: Aphididae: Aphidinae). All insect cultures were stored in the High-Security Containment/Quarantine Facility in St. Paul, MN. Host range test was conducted in this facility as well.