Insects of the family Nabidae (Hemiptera) are generalist predators commonly found in agroecosystems, but little is known about their predation rates on common pests of forage crops. We determined the functional response and prey preference of Nabis Latreille species to two common leafhopper pests of red clover (Trifolium pratense Linnaeus; Fabaceae): Agallia constricta Van Duzee (Hemiptera: Cicadellidae) and Ceratagallia agricola (Hamilton) (Hemiptera: Cicadellidae). We also determined the survivorship of A. constricta to predation by Nabis species over the course of five days. The Nabis species displayed a Type III functional response to both leafhopper species with a preference for A. constricta. The 10-A. constricta/cage treatments and 20-A. constricta/cage treatments had the highest survival probabilities after five days with survival probabilities of 0.19 and 0.23, respectively. These results indicate that Nabis species may help in controlling leafhopper populations in forage-crop systems.