The soybean aphid, Aphis glycines Matsumura (Homoptera: Aphididae), is an economic pest of soybeans in the United States. In their native range of China, natural enemies maintain A. glycines as a non-pest on soybeans. Multitrophic interactions of herbivores, their host plant and natural enemies can be linked, with herbivores inducing the emission of plant volatiles that play both a direct and indirect defensive role. We investigated if the volatile emissions from soybean plants are altered due to A. glycines herbivory. Vegetative stage soybeans were infested with 10 A. glycines nymphs and populations were allowed to develop over 14 days. Leaves from five infested and uninfested plants were placed in individual vials and volatiles were sampled for 24 h using a single solid phase microextraction Carboxen/PDMS-75 micrometer fiber placed in the headspace. More than 50 compounds emitted by infested and uninfested leaves were identified using multidimensional gas chromatography-mass spectrometry. A component of the volatiles released by aphid-infested soybean was methyl salicylate. We confirmed the presence of methyl salicylate from soybean leaves using pure compound and calculated its relative abundance from excised leaves. Significantly (Students T-test with Satterhwaite correction for unequal variances; t=2.80, df=4.2, P=0.05) more methyl salicylate was produced by A. glycines infested than uninfested plants. Methyl salicylate has been shown to be an insect and mite herbivore induced plant odor that attracts insect predators in other systems. Based on these results we hypothesize that soybeans employ an indirect defense against A. glycines that includes methyl salicylate.