One of the serious detriments to soybean (Glycine max (L.) Merr.) cultivation in the State of S. Paulo, Brazil, are root-parasitic nematodes. A study of infected material collected at Bauru, where at least two distinct soybean varieties were cultivated, disclosed that three forms were involved: a meadow nematode (Pralylenchus sp.) and two root-knot nematodes (Meloidogyne incognita (Kofoid & White, 1919) Chitwood, 1949, and M. javanica bauruensis n. subsp.). Silva, Lordello & Miyasaka (3) published some observations about the resistance of several soybean varieties to the attacks by root-knot nematodes in Campinas. A detailed study of the nematodes involved in those experiments, which were considered as related do M. incognita, has not yet been made. One of the varieties tested, La 41-1219, proved to be resistant, thereby providing promising material for further studies and breeding. Unfortunately, such a variety when planted in Bauru, was severely attacked by a root-knot species, which is identified as M. incognita. Attacks by M. javanica bauruensis was not noted in that variety but was noted in another variety (Abura) growing adjacent in the same field. The host preference of those two nematodes was specific and very marked. M. incognita attacked only var. La 41-1219 and M. javanica bauruensis only var. Abura. Invasions by meadow-nematodes were equally observed in the two varieties concerned. In this paper, the study of M. javanica bauruensis n. subsp. is made with all the details possible. It differs from the typical subspecies (M. javanica javanica (Treub, 1885) Chitwood, 1949), in having : a) eggs usually wider (37.0-52.5 : 31.0-40.0 micra); 6) stylet of larvae somewhat longer (11.0-11.6 :10.0 micra); c) neck of larvae longer (b1 = 6.1-6.5 :b = 6.3-8.0); d) head of male with a single post-labial annule instead of the two or three present in the typical subspecies; e) lateral lines in the perineal pattern less evident and not extending to cervical region, with some striae extending unbroken from dorsal to ventral sectors; and, f) higher arch in the perineal pattern, composed of marked wavy to zig-zag striae. In the population studied, several males were found for which the term intersex is applied. The less evident alteration that was seen affects only the shape of the male body, which is considerably thicker in its posterior portion and visibly shorter in its total length. The lateral fields are wider at the latitude of the thick portion, where additional incisures can be counted. In the most advanced case of intersexuality observed besides the same alteration in the shape of the body, there is a vulva and traces of a vagina very well defined. Some data about the M. incognita population obtained in association with M. javanica bauruensis are also presented. - Such a population only differed from that studied by Chitw r ood (1) in having shorter and more slender larvae and males with shorter spicules. Very short males were also observed their total length lying between 690 and 900 micra.