Two F2 populations of cotton (Gossypium hirsutum L.) were analyzed with restriction fragment length polymorphism (RFLP) technology. An F2 population from the cross of HS46 x MARCABUCAG8US-1-88 was analyzed with 73 probe/enzyme combinations which resulted in 57 polymorphic fragments representing 25 polymorphic loci. Of these polymorphic loci, 14 were codominant and 11 were +/- genotypes. Two linkage groups spanning 123 and 0.5 cM were established with 9 and 2 loci, respectively. The 14 remaining loci were unlinked. Studies are presently being done to associate these molecular markers with fiber traits. In another cross, fifty F2 plants from a population of ST453 x M315 were analyzed with 31 probe/enzyme combinations that resulted in 24 polymorphic fragments. These fragments represented 13 polymorphic loci. Two of these loci were codominant while 11 were +/- genotypes. Six loci were paired into 3 linkage groups of 2 loci each, while the remaining 7 loci were unlinked. These loci are being studied in an attempt to find a molecular marker for root-knot nematode (Meloidogyne incognita (Kofoid and White) (Chitwood)) resistance.