Genetic diversity among 126 upland cotton cultivars released between 1980 and 1990 in the United States was assessed by coefficient of parentage. Cluster analysis of coefficient of parentage revealed 12 distinct gene pools. Mean coefficient of parentage within clusters ranged from 0.10 for cluster 7 to 0.34 for cluster 4, both composed of plains type cultivars. Delta and Southeastern cultivars clustered into 4 distinct gene pools. The cluster composed primarily of DeltaPine cultivars was the least genetically diverse, with mean coefficient of parentage greater than that for half-sibs with inbred parents, followed by clusters with cultivars of Coker, Pee Dee, and Stoneville origin. The New Mexico and California Acala cultivars formed one cluster and were not highly related (mean coefficient of parentage = 0.15) and were genetically distinct from the remaining 11 clusters (Mean between cluster coefficient of parentage ranged from 0.01 to 0.06). These data indicate that some substantially related groups of cultivars exist among the 126 released between 1980 and 1990. The opportunity exists, however, to consider making crosses between cultivars from different clusters with the potential to release more genetic variation than that from mating cultivars within clusters.