The ability of the soybean cyst nematode (Heterodera glycines) to reproduce on eight weed species commonly occurring in Iowa was evaluated in greenhouse and field microplot experiments. Population densities of the nematode increased on H. g/ycines-susceptible soybean but not on H. g/ycines-resistant soybean, Canada thistle, cocklebur, eastern black nightshade, giant foxtail, lambsquarters, redroot pigweed, velvetleaf, and wild sunflower. All of the weeds evaluated were nonhosts of this H. glycines race 3 population.