Twenty-nine species of sunflower (Helianthus) andViguiera porteri(Gray) Blake were evaluated in the laboratory for resistance to the western potato leafhopper,Empoasca abruptaDeLong. Leafhopper development was significantly (5% level) prolonged and survival was significantly decreased on most of theHelianthusspecies than on cultivatedH. annuusL., hybrid variety 896 when plants were initially colonized by nymphs. Colonization of plants by adult leafhoppers resulted in significantly smaller (10% level) populations on 14Helianthusspecies but significantly larger populations on 3Helianthusspecies than on hybrid 896 1 month after the initial infestation. Injury to plants of mostHelianthusspecies ranged from no symptoms to moderate chlorosis 7 days after infestation, but plants of 20 species exhibited moderate chlorosis to wilting after 1 month. Eight of the resistantHelianthusspecies could be utilized as a source of leafhopper resistance in cultivated sunflower quite readily because of their crossing compatibility.