Technical Abstract: An RFLP genetic linkage joinmap was amalgamated from four different genetic backgrounds of Gossypium hirsutum L. mapping populations (Delta, Acala, and Texas plain), two previously reported by Ulloa and Meredith (2000) and Shappley et al. (1998). The four populations were analyzed with a total of 248 probe/enzyme combinations resulting in 452 RFLP loci and two morphological markers (pollen color, P1 and leaf shape, L2), making a total of 454 loci. A core of 104 cDNA clone-probes was shared between populations, yielding 111 RFLP loci. The joinmap from the four populations comprises 283 loci, from 201 cDNA probe/enzyme (EcoRI and EcoRV) combinations and the locus for P1, mapped to 47 linkage groups with the average distance between markers of 5.3 cM, covering 1502.6 cM or approximately 31% of the total recombinational length of the cotton genome. In general, breeding pedigree data agreed with RFLP data where parents with similar gene pools had the least number of polymorphic RFLP loci for a given population. The genetic joinmap provides further knowledge of existing genetic diversity by representing possible ancestral synteny and gene order of the cotton genome before domestication and breeding, which narrow its genetic base.