Except for four species of the Mertensinematinae (Molineoidea) not considered in this work, the Trichostrongylina parasitic in amphibians and reptiles, comprising 15 genera and 105 species, are reviewed. The morphological characteristics of each species are analysed. The most important characteristics are provided by the disposition of the caudal bursal rays, the morphology of the synlophe (at the oesophago-intestinal junction and mid-body level) and by the anatomy of the spicules. The species are classified into seven groups: