Approximately 80 species of Trypanosoma are described from reptilian hosts, represented by 11 in chelonians, 48 in lizards, 20 in snakes, and 2 in crocodilians. Some of these, perhaps, are synonyms. There are many reports of trypanosomes simply as Trypanosoma sp. (Brygoo, 1966b), some of which are probably valid species. Inadequate descriptions containing few morphometric data were provided for many of them. Although there is great variability in form, with adequate morphological data a species can usually be distinguished from others, especially in the case of saurian trypanosomes. Life cycles and natural vectors are poorly known, and only Trypanosoma platydactyli has been examined biochemically.