Numbers of root-knot nematode (RKN) (Meloidogyne incognita acrita) [Kofoid and White] Chitwood) eggs produced on 18 cotton (Gossypium hirsutum L.) cultivars and lines in a series of greenhouse tests ranged continuously from 1,000/plant on the breeding stock Auburn 623 RNR to 148,000/plant on 'Rowden'. Fusarium wilt disease (FW) (Fusarium oxysporum Schlecht. f. vasinfectum [Atk.] Synd. & Hans.) wilting percentages of the same cottons in a series of field tests ranged continuously from 3% on Auburn 623 RNR to 98% on Rowden. FW percentage was correlated (r=0.73, P=<0.01) with numbers of RKN eggs produced. This correlation was even higher (r=0.91, P=<0.01) when data were omitted for two cultivars that were unique by having low wilting percentages combined with high RKN egg production. These two cottons apparently contained a resistance mechanism independent of RKN resistance that reduced susceptibility to wilting. The 18 cottons were also stem-inoculated with Fw fungus in a series of greenhouse tests. This permitted expression of FW disease independent of RKN effects. Seven of the cottons with lowest RKN reproduction had much lower wilting in the field compared with that from stem inoculation, while seven with highest RKN reproduction had much higher field wilting compared with wilting from stem inoculation. Results of these studies indicated that some cottons studied had moderate levels of FW resistance without RKN resistance. However, high RKN resistance alone provided equal or higher FW resistance than Fusarium resistance alone, and extremely high FW resistance apparently depended on extremely high RKN resistance.