Parasitoids and predatory flies that can attack soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae), in soybean, Glycine max (L.) Merr., fields were identified 3 to 4 yr after the aphid was first sighted in the north central United States. We detected 15 species by exposing soybean aphid to ovipositing parasitoids and predatory flies at two locations in southern Michigan. The species detected were (in order of the number of specimens recovered from high to low) Aphidoletes aphidimyza Rondani (Diptera: Cecidomyiidae), Lysiphlebus testaceipes Cresson (Hymenoptera: Braconidae), Allograpta obliqua Say (Diptera: Syrphidae), Aphidius colemani Viereck (Hymenoptera: Braconidae), Eupeodes americanus Wiedemann (Diptera: Syrphidae), Leucopis glyphinivora Tanasijtshuk (Diptera: Chamaemyiidae), Aphelinus asychis Walker (Hymenoptera: Aphelinidae), Sphaerophoria contigua Macquart (Diptera: Syrphidae), Binodoxys kelloggensis Pike, Starý & Brewer (Hymenoptera: Braconidae), Eupeodes volucris Osten Sacken (Diptera: Syrphidae), Paragus hemorrhous Meigen (Diptera: Syrphidae), Toxomerus marginatus Say (Diptera: Syrphidae), Aphelinus albipodus Hayat & Fatima (Hymenoptera: Aphelinidae), Syrphus rectus Osten Sacken (Diptera: Syrphidae), and Praon sp. (Hymenoptera: Braconidae). These species were capable of finding, attacking, and completing development on soybean aphid in soybean fields. Based on a literature review, host aphid ranges of the species detected varied widely, with a tendency toward broader host ranges. These data add to the existing information on the predatory complex currently known to attack soybean aphid in the north central United States. Implications for biological control of soybean aphid are discussed.