In field microplot experiments, infection of cotton, Gossypium hirsutum ITM-11 by a nonpathogenic or pathogenic race of the root-knot nematode (Meloidogyne incognita), races 1 and 3 respectively, indicated that either race of the nematode could reduce the number of bolls per plant thus reducing the yield of seed cotton compared to noninoculated plants. The greatest reduction in yield was observed from plants inoculated with the nonpathogenic race of the nematode. The race of the nematode, however, did not seem to differentially effect the distribution of boll set on the plant. Compared to the noninoculated controls, neither race 1 nor race 3 of the nematode affected fiber length. Both race 1 and race 3 slightly increased the fiber maturity value. Fiber micronaire was increased slightly by infection by either race of the nematode. Fiber fineness was uniformly poor even from noninoculated controls. None of the differences observed were validated at the .05 level.