The soybean aphid, Aphis glycines Matsumura (HOMOPTERA: APHIDIDAE), is a recently introduced pest of soybeans in North America. The damage estimates due to this pest are projected to be in the billions of dollars in the United States. Since 2000 when soybean aphid was detected in Wisconsin, many universities, and other entities have initiated studies on this insect and its possible control methods. Plant resistance to this aphid sp. is one important component of integrated control. We compared the development of aphid populations on several soybean lines in a pesticide-free greenhouse. Six adults per plant were placed in the upper side of the leaves and seven days later the number of adults and nymphs was counted. The most promising of these lines showing fewer nymphs were selected for characterization of antibiosis in a true non-choice test. Adults were confined in double-sided sticky cages stuck to the upper side of leaves; new offspring were counted and removed daily for five continuous days.