Longidorids are a group of polyphagous nematodes and ectoparasites of the root, usually associated with herbaceous plants. They can tolerate very dry or very humid soils. The distribution of this group of nematodes in the soil is conditioned by temperature, soil type and vegetation, whilst in the vertical distribution, soil texture, humidity and hosts are the predominant factors. They feed on the tip of the root, causing darkening of the tissue, hyperplasia, proliferation of the lateral roots and, in some cases, knots. The longidorids have received more attention since it was discovered that Xiphinema index was the vector of the virus of the grapevine leaf (Grapevine fanleaf virus - GFLV-) This nematode is of worldwide distribution, being the grapevine its main host. The species transmitting viruses are the most relevant because of the economic importance they acquire. This review provides information about these nematodes at a generic level, updating the list of species present in South America, the species transmitting viruses in Argentina and the quarantine species of Argentina and Uruguay.