Stable performance in crop yield and quality traits over a wide range of growing conditions is desirable for management, marketing, and profit. Tests were conducted over a two-year period, 1991 and 1992, at six locations in the Guadalquivir Valley, Spain. Six cultivars were tested. Data were analyzed using the AMMI method. Averaged over years and locations, mean seedcotton yield ranged from 3895 kg/ha for Stoneville 506 to 4353 kg/ha for Tabladilla 16. Environments, genotypes, genotype* environment (G*E) interaction were highly significant. PCA1 of the principal component analysis accounted for 54.2% of the G*E variance and PCA2 for 34.2%. None of the cultivars showed general adaptability to all six environments. Deltapine 90 and KNX-111 were stable in the "Las Marismas" region which is characterized by its salty-clay soils and high Verticillium wilt infestation. Tabladilla 16 and Coker 139 were adapted to four regions in the Guadalquivir Valley, form Jaen to Sevilla.