The cotton varieties Acala NemX and Stoneville LA887 have resistance to the root knot nematode Meloidogyne incognita. No data exist on the inheritance of resistance or whether resistance is due to unique genes. Genetic experiments crossed each cultivar with the susceptible cultivar Deltapine 90. Acala NexX was also crossed with Stoneville LA887. Tests rated F1 and F2 individuals from each cross for resistance based on nematode reproduction measured as eggs per gram of roots and root gall indexes. In both crosses with Deltapine 90, approximately 20 percent of F1 individuals were resistant. The F2 from susceptible F1 segregated in a ratio of one resistant to three susceptible genes for both crosses, indicating that resistance was inherited as a single recessive gene. Resistance segregation in F2 from resistant F1 indicated that resistance was inherited as two dominant genes. All of the F1 and F2 individuals from the Acala nemX x Stoneville LA887 cross were resistant, suggesting that resistance may have resulted from the same recessive resistance gene. Abstract.