The intrafamilial relationships of the Gentianaceae are investigated by means of a cladistic analysis based on morphological and to a lesser extent on chemical data. The 21 genera that are selected for the analysis represent all tribes and subtribes except Leiphaimeae, Rusbyantheae and Voyrieae. The large genus Gentiana is represented by three of its sections. The former loganiaceous genera Anthocleista and Fagraea are used as outgroups. Standard parsimony analyses and analyses using weights that are based on the cladistic reliability of the characters give congruent results as far as the global relationships are concerned The best supported clade contains Eustoma (Tachiinae) and all included Gentianinae, Erythraeinae and Chironiinae. The basal division in this clade is between Ixanthus and the other genera. In this way Ixanthus, an endemic of the Canary Islands, connects the mostly woody tropical and the mostly herbaceous temperate taxa. Subtribe Gentianinae (excluding Ixanthus) is monophyletic, unlike Erythraeinae and Chironiinae. In most analyses, however, both subtribes together (and including Eustoma) are the sister-group of Gentianinae. possibly Erythraeinae, Chironiinae and Eustoma should be merged. The basal parts of the cladograms, involving the woody tropical representatives and Exacum, are poorly resolved. More extensive sampling, especially among the tropical representatives, is necessary to elucidate these basal relationships. The tropical ancestry of the family,the switch from a woody to a herbaceous life form, and the position of critical taxa, such as Swertia and Halenia or Tripterospermum, are discussed.