The adults and larvae of the South-American Gomphidae are classified. Keys to the subfamilies and tribes are constructed followed by tribal descriptions and descriptive notes. The existing classification is revised as follows: - Octogomphinae comb. nov.: Hemigomphini (Neogomphus, Praeviogomphus), Anomalophlebiini trib. nov. (Anomalophlebia); - Onychogomphinae: Onychogomphini (Erpetogomphus); - Epigomphinae: Archaeogomphini (Archaeogomphus), Agriogomphini trib. nov. (Agriogomphus, Brasiliogomphus, Ebegomphus), Cyanogomphini comb. nov. (Cyanogomphus, Tibiagomphus), Epigomphini (Epigomphus); - Ictinogomphinae comb. nov.: Ictinogomphini comb. nov. (Cacoides, Melanocacus); Zonophorinae: Zonophorini (Mitragomphus, Zonophora); - Gomphoidinae comb. nov.: Aphyllini trib. nov. (Aphylla, Phyllocycla), Diaphlebiini trib. nov. (Desmogomphus, Diaphlebia), Gomphoidini comb. nov. (Gomphoides, Idiogomphoides, Phyllogomphoides), Peruviogomphini trib. nov. (Peruviogomphus), Progomphini (Progomphus).