AbstractThis chapter presents the classification, biochemical and molecular diagnostics and management of ectoparasitic nematodes, including those belonging to Chromadoria and Enoplea (Longidoridae and Trichodoridae). Ectoparasitic tylenchs sensu stricto can be grouped according to their parasitic strategies: (i) the migratory ectoparasites, which stay vermiform throughout their life cycle and feed for short periods along the root system (e.g. Trichodorus, Belonolaimus, Dolichodorus); and (ii) the sedentary ectoparasites, which are those species that may feed for several days on the same cell, either a cortical or an epidermal cell. The Longidoridae and Trichodoridae are migratory root ectoparasites. They are responsible for substantial direct damage to a wide variety of plants, but their major pest status is as virus vectors, despite the rather low number of vector species in both families.