Of 36 wild rices screened, 19 accessions were resistant or moderately resistant to three biotypes of the brown planthopper,Nilaparvata lugens(Stål), and 9 were resistant or moderately resistant to at least one biotype. Resistant accessions were nonpreferred andN. lugenscaged on resistant accessions had low food ingestion rates, slow nymphal development, reduced longevity, low fecundity, and consequently low populations. Two wild rice species decreased the percent hatchability ofN. lugenseggs. Some moderately resistant accessions have tolerance toN. lugens, as indicated by low plant damage ratings and plant loss and high percentageN. lugenssurvival and weight gain. Wild rices are possible sources of new genes forN. lugensresistance.