An experiment was instituted to incorporate resistance to the powdery mildew fungus <i>Erysiphe cichoracearum</i> DC into the Ambrosia muskmelon, a melon of the Casaba or winter type. First generation hybrid (F1), first generation backcross (B1) and second generation inbred (F2) plants were grown to maturity at Blacksburg and Warsaw, Virginia. On the basis of the data obtained the following conclusions are drawn: • The muskmelon material acquired from the Plant Exploration and Introduction Service is a good source of powdery mildew resistance and of the material tested, PI3 showed the most promise as a source of commercial resistance. • The general technique of hybridizing a susceptible with a resistant plant can be used to advantage in incorporating disease resistance into the Ambrosia melon. • Further work is needed to obtain a commercially acceptable Ambrosia melon which is essentially homozygous for resistance to powdery mildew, and to determine the exact mechanism of inheritance of powdery mildew resistance. / Master of Science