Cotton fields in the San Joaquin Valley of California were sampled for Meloidogyne incognita using a proportional random sample based on the presence of a pink bollworm trap. The soil samples were bioassayed for the presence of root-knot nematode using a susceptible tomato cultivar. In 1990, 362 soil samples were taken from Kern, Kings, and Tulare Counties with 23.4% being infested with root-knot nematode. In 1991, 389 samples were taken from Fresno, Madera, and Merced Counties with 17.7% being infested. The overall average of 20.5% of soil samples with root-knot nematode supports distribution estimates for inferring crop loss.