Reproduction and development of western flower thrips were evaluated on cotton genotypes. Asiatic cotton (Gossypium arboreum L.), accession A2-154 and upland cotton (Gossypium hirsutum L.), cultivar Deltapine 458 BGRR were used as resistant and susceptible genotypes, respectively. No thrips pre-adult developmental differences were found between the two cotton genotypes. Adult longevity of thrips reared on Deltapine 458 BGRR was significantly greater than those reared on A2-154 with 18.64 and 15.14 days, respectively. Also, the average number of thrips larvae produced per day was significantly greater on Deltapine 458 BGRR.