Varieties of glandular-haired alfalfa, Medicago sativa L., with resistance to the potato leafhopper, Empoasca fabae (Harris), have been commercially released. To assess the role of volatile organic compounds in leafhopper resistance, stem and leaf volatiles were collected using vacuum steam distillation and head-space analysis from resistant, glandular-haired M. sativa cv. ‘G98A’ and susceptible, nonglandular M. sativa cv. ‘Ranger’. Gas chromatography-mass spectrometry determined that steam distillates from both G98A and Ranger were composed mainly of alcohols and esters, with 1-octen-3-ol frequently being the predominant compound in steam distillates, and (Z)-3-hexenyl acetate and (Z)-3-hexen-1-ol as other major components. (Z)-3-hexenyl acetate was the only major component in head-space samples from G98A and Ranger. No volatiles were unique to either G98A or Ranger. Two-choice bioassays of leaf steam distillates and head-space samples found significantly more potato leafhoppers oriented towards volatiles from Ranger than G98A. However, leafhoppers were not attracted to either (Z)-3-hexenyl acetate or 1-octen-3-ol when tested singly. Leafhoppers may be more attracted to M. sativa Ranger than M. sativa G98A.