Many cotton cultivars with resistance to the Fusarium wilt/root-knot nematode complex are susceptible to nematode reproduction. The objective of this response was to determine the response of such a cultivar to nematicide treatment in soil infested with Meloidogyne incognita. The cultivar Paymaster HS26, with excellent resistance to the Fusarium wilt/root-knot complex, was compared to the germplasm line 1322 RNR, which is resistant to nematode reproduction. Plants were grown in field microplots in a sandy soil infested with 80 eggs & J2 of M. incognita/500 cm3 and treated with 0, 0.45, or 1.5 lb a.i. aldicarb treatments were observed with respect to root-galling and final nematode population densities. The resistant germplasm line 1322 RNR had reduced (P = 0.05%) galling and lower nematode populations than did Paymaster HS26. Aldicarb treatments resulted in lower (P = 0.05%) final nematode population densities relative to the no aldicarb treatment for both cotton genotypes. Seed cotton yield responses to treatments were generally not significant but there was a trend for greater yield suppression by the nematodes on Paymaster HS26 relative to 1322 RNR, and that yields of Paymaster HS26 were increased by treatment with aldicarb. These data confirm the susceptibility of Paymaster HS26 to nematode reproduction and provide evidence that this cultivar is intolerant with respect to yield, of infection by root-knot nematodes.