Plant trypanosomes have never been at the forefront of plant pathology matters. Even today, they hold only a marginal place among plant pathogens. There are two main reasons for this isolation: (1) the diseases caused by trypanosomes are confined to northern Latin America and the southern Caribbean; and (2) they affect only a small number of cultivated plants. It can also be added that the outbreak of one such disease, on coffee in a small country, Suriname (a Dutch colony at the time), became a real problem only during 1930–1950, a time during which the economic effects of World War II were at least as important, if not more important, to the coffee industry, and the publications concerning the outbreak were in German. Finally, because it was impossible at the time to isolate these organisms and culture them in vitro, the scientific community, including plant pathologists and parasitologists, lost interest in them. In this chapter we shall see that plant trypanosomes are of great interest in different respects, including parasitology, the evolution of members of Trypanosomatidae, parasite biology, plant pathology, transmission and insect vectors, and epidemiology.