Four cotton breeding lines with high levels of resistance to both M. incognita and F. oxysporum f.sp. vasinfectum were compared the commercial cotton cultivar 'Stoneville 825' with and without aldicarb (1.5 lb/A) in a field infested with high levels of both M. incognita and F. oxvsporum f.sp. vasinfectum. By midseason, Stoneville 825 plots without aldicarb were characterized by 50-70% plant mortality and exhibited typical vascular discoloration and severe root galling. Application of the nematicide resulted in less severe wilting and root galling but did not give acceptable plant survival from a production standpoint. Resistant Auburn 634 and lines 87-1781, 87-1793, and 87-1813 were characterized by < 1% plant mortality and very low wilt and root gall indices. Yield data from these plots indicate the significance of high levels of genetic resistance to these pathogens in commercial cotton production.