A method is described for screening winter wheat hybrids for resistance to the greenbug, Toxoptera graminum (Rond.). Of 1,026 F2 plants screened, which were grown from resistant susceptible crosses, 28 showed considerable resistance and were grown to maturity in the greenhouse. The F3 families, grown from the F2 plants, were screened along with 190 unselected F3 families. The high percentage of resistant F3 families obtained from the resistant F2 plants indicates progress in selecting for greenbug resistance. Results suggest that resistance is controlled by a single factor pair with susceptibility being dominant to resistance, although modifiers may be involved.