The root-knot nematode (RKN), Meloidogyne incognita (Kofoid and white) Chitwood, is a serious pest of cotton. A two-year study was conducted to evaluate the field performance of selected cotton genotypes; ['Deltapine 411 (DPL 41), 'Stoneville LA8871 (STV 887), LAS30909, LA830873, LAS61885, M-155, M-249, M-315, and M-725] under heavy RKN infestation at the Red River Research Station id Bossier City, Louisiana. The commercial varieties, DPL 41 and STV 887, were used as susceptible and resistant checks, respectively. Other genotypes had shown resistance to RKN in greenhouse tests, but had not been extensively tested under field conditions. Genotypes were evaluated in plots treated with either aldicarb [2-methyl-2-(methylthio) propionaldehyde O- (methylcarbamoyl) oxime] (Temik) or O,O-Diethyl S-[2-(ethylthio)ethyl] plosphorodithioate (Di-syston) as in-furrow treatments. Lint yield, RKN population fluctuation, lint percentage and fiber properties were measured. Lint percentage and fiber properties were not significantly affected by in-furrow treatments, however significant genotypic differences existed. STV 887 had the highest lint percentage at 41.6%, while the highest lint percentage for the Mississippi genotypes was M-315 with 39.5%. LA830909 had the highest micronaire and longest fibers with 4.9 and 1. 17 in., respectively, while the highest micronaire and length among Mississippi genotypes were 4.6 for M249 and M-315, and 1.15 in. for M-249, respectively. STV 887 had the strongest fibers at 28.8 g/tex. The Mississippi genotypes with the strongest fibers were M249 and M-725 with 26.8 g/tex. In-furrow treatments had a significant main effect on lint yield. Temik treated plots produced 126 lbs/A more lint than Di-syston treated plots, averaged across all genotypes. Only DPL 41 suffered significant yield loss in Di-syston vs. Temik treated plots. Averaged across in-furrow treatments STV 887 was the highest yielding genotype tested, with 893 lbs/A, while M-155 was the highest yielding Mississippi genotype at 814 lbs/A. Temik reduced RKN populations averaged across genotypes, although not statistically. Cotton genotypes had a significant main effect on RKN populations. Combined over in-furrow treatments, RKN counts ranged from 1478 per pint of soil (pps) to 169 pps for DPL 41 and M-155, respectively. Only DPL 41 had significantly more RKN than other genotypes averaged over both years. The degree of galling was only rated in Di-syston treated plots. DPL 41 exhibited more galling than all other genotypes, each year and averaged across years. RKN resistant genotypes from Mississippi have a lower yield potential than Louisiana strains tested, but maintain RKN at fairly low levels throughout the growing season. Louisiana genotypes yield well but had a numerically lower level of RKN resistance than the Mississippi genotypes.