Growth chamber, microplot, and field tests evaluated sun hemp (Crotalaria juncea) and kenaf (Hibiscus cannabinus) as rotational fiber crops for managing nematode pests in cotton. Each test included kenaf cv. Everglades 71, sunn hemp cv. Tropic Sun, and a cotton cultivar (Delapine 16 or Deltapine 50) susceptible to race 3 of Meloidogyne incognita (the cotton root-knot nematode), as the experimental control. Additional entries included the sunn hemp genotypes TX-374 and IAC 1-2 in the growth chamber test, the resistant cotton genotype Auburn 623 in the growth chamber and microplot test, and the kenaf lines SF 459 and SF 192 in the field test. In the growth chamber and microplot experiments, each genotype was tested separately against M. incognita and Rotylenchulus reniformis (the reniform nematode). In the field experiment, soil was naturally infested with a mixed population of the two nematodes. The results indicated that sunn hemp cv. Tropic Sun and probably other sunn hemp genotypes will reduce nematode problems in a cotton rotation. Everglades 71 kenaf also can be used in rotation with cotton where R. reniformis but not M. incognita is present. If used where M. incognita is present, Everglades 71 can increase the population density of M. incognita to a level that is devastating to cotton.