The cotton fleahopper, Pseudatomoscelis seriatus Reuter, is a widespread and important insect pest of cotton in Texas and Oklahoma. This plant bug feeds on small floral buds, which results in bud abscission, delayed fruiting, and subsequent crop loss. In central and southeastern Texas, two to four insecticide applications are typically applied for cotton fleahopper management. Primitive race stocks of cotton have been identified as an important source of resistance to a wide range of insect pests, but they have not been evaluated for resistance to cotton fleahopper. The objective of this study was to evaluate selected groups of primitive race stocks of Gossypium hirsutum L. for resistance to cotton fleahopper. Resistance was identified by caging cotton fleahoppers on cotton plants in a no-choice feeding trial and comparing the mean number of damaged squares per plant to a standard susceptible genotype. Four primitive race stocks, TX706, TX188, TX1530, and TX1156, were identified as resistant to cotton fleahopper in a collection of 65 primitive race stocks representing 18 genetic groups and collected throughout Mexico and Central America. No resistance was found in a collection of 11 accessions previously identified as resistant to Lygus spp. and no resistance was identified in a collection of 78 primitive accessions converted to day-neutrality. The possibility that some genetic resistance in these race stocks to the cotton fleahopper might have been lost as a result of the conversion to day-neutrality is discussed.