The root-knot nematode Meloidogyne javanica (Treub, 1885) Chitwood, 1949, was identified in roots, nodules and shells of peanut plants (Arachis hypogaea L.), cv. Florman-INTA, collected from a field in Menno colony, Chaco Central region of Paraguay. Infected plants were observed in patches, showing wilting and drying of vegetative parts. Peanut had been grown ininterruptly for many years in the same area and patches had already been observed in the preceding year in cv. Starr. Nematodes collected from roots in this field reproduced on tomato cultivar rutgers and peanut cultivar florunner and produced egg-masses on roots, nodules and shells of cultivar Florman. This is the first report on M. javanica parasiting peanut in Paraguay.