Many accessions of cotton are  known to have resistance to root-knot nematodes, but inheritance of resistance and allelic relations have not been studied in most of these accessions.  This study compares inheritance of resistance in five primative accessions from Mexico with inheritance in the accessions Clevewilt-6 and Wild Mexico Jack Jones.  Resistance in the different accessions appears to be inherited mostly as two or more genes, in some instances resistance appears to be a recessive trait whereas in other accessions resistance is a dominant trait.  These data suggest that there are multiple genes for resistance which suggests that by using multiple different alleles it should be possible to develop durable resistance.