Discovered in 1909, plants trypanosomatids (Protozoa Kinetoplastida) have been immediately classified in an arbitrary genus "Phytomonas" to distinguish them from flagellate parasites of mammals. This taxonomic classification is problematic because it puts together organisms which have many biological, biochemical and molecular differences. Plant trypanosomatids scientists now agree to separate "Phytomonas" in three main groups including phloem restricted trypanosomatids. These are associated with wilt of oil palm (Marchitez) and coconut tree (Hartrot), and they are endemic in South America. We have studied new or doubtfully classified isolates by RAPD. We tested different primer choices and different ways to read the gels. The various dendrograms obtained have been compared. In conclusion, the influence of the crude data process on the main sub-groups of trypanosomatids is not important.