Field-collected Agonum muelleri (Herbst) adults were videotaped to assess their ability to climb soybean (Glycine max (L.) Merr. (Fabaceae)) plants. All individuals climbed up and down soybean plants multiple times. Agonum muelleri spent from 12.5 ± 3.4% to 54.1 ± 11.3% of their time on soybean plants. Caged A. muelleri adults on plants infested with soybean aphids, Aphis glycines Matsumura (Hemiptera: Aphididae), reduced the number of apterous adults. The presence of predators had an indirect effect on the density of nymphal aphids by reducing the numbers of adult aphids. Agonum muelleri, an abundant carabid in soybean fields, readily climbs soybean plants to feed on soybean aphids.