Spilomelinae and Pyraustinae form a species-rich monophylum of Crambidae (snout moths). Morphological distinction of the two groups has been difficult in the past, and the morphologically heterogenous Spilomelinae has not been broadly accepted as a natural group due to the lack of convincing apomorphies. In order to investigate potential apomorphic characters for Spilomelinae and Pyraustinae and to examine alternative phylogenetic hypotheses, we conduct a phylogenetic analysis using 6 molecular markers and 114 morphological characters of the adults representing 77 genera of Spilomelinae and 18 genera of Pyraustinae. The results of the analysis of the combined data strongly suggest that Spilomelinae and Pyraustinae are each monophyletic and sister to each other. Wurthiinae is confirmed as ingroup of Spilomelinae, and Sufetula Walker, 1859 as a non-spilomeline. Within Spilomelinae, several well supported clades are obtained, for which we propose a first phylogeny-based tribal classification, using nine available and four new names: Hydririni Minet, 1982 stat.rev., Lineodini Amsel, 1956 stat.rev., Udeini trib.n., Wurthiini Roepke, 1916 stat.rev., Agroterini Acloque, 1897 stat.rev., Spilomelini Guenée, 1854 stat.rev. (= Siginae Hampson, 1918), Herpetogrammatini trib.n., Hymeniini Swinhoe, 1900 stat.rev., Asciodini trib.n., Trichaeini trib.n., Steniini Guenée, 1854 stat.rev., Nomophilini Kuznetzov & Stekolnikov, 1979 stat.rev. and Margaroniini Swinhoe & Cotes, 1889 stat.rev. (= Dichocrociinae Swinhoe, 1900; = Hapaliadae Swinhoe, 1890; = Margarodidae Guenée, 1854). The available name Syleptinae Swinhoe, 1900 could not be assigned to any of the recovered clades. Three tribes are recognized in Pyraustinae: Euclastini Popescu-Gorj & Constantinescu, 1977 stat.rev., Portentomorphini Amsel, 1956 stat.rev. and Pyraustini Meyrick, 1890 stat.rev. (= Botydes Blanchard, 1840; = Ennychites Duponchel, 1845). The taxonomic status of Tetridia Warren, 1890, found to be sister to all other investigated Pyraustinae, needs further investigation. The four Spilomelinae tribes that are sister to all other, ‘euspilomeline’ tribes share several plesiomorphies with Pyraustinae. We provide morphological synapomorphies and descriptions for Spilomelinae, Pyraustinae and the subgroups recognised therein. These characters allow the assignment of additional 125 genera to Spilomelinae tribes, and additional 56 genera to Pyraustinae tribes. New and revised combinations are proposed: Nonazochis Amsel, 1956 syn.n. of Conchylodes Guenée, 1854, with Conchylodes graphialis (Schaus, 1912) comb.n.; Conchylodes octonalis (Zeller, 1873) comb.n. (from Lygropia); Hyperectis Meyrick, 1904 syn.n. of Hydriris Meyrick, 1885, with Hydriris dioctias (Meyick, 1904) comb.n., and Hydriris apicalis (Hampson, 1912) comb.n.; Conogethes pandamalis (Walker, 1859) comb.n. (from Dichocrocis); Arthromastix pactolalis (Guenée, 1854) comb.n. (from Syllepte); Prophantis coenostolalis (Hampson, 1899) comb.n. (from Thliptoceras); Prophantis xanthomeralis (Hampson, 1918) comb.n. (from Thliptoceras); Prophantis longicornalis (Mabille, 1900) comb.n. (from Syngamia); Charitoprepes apicipicta (Inoue, 1963) comb.n. (from Heterocnephes); Prenesta rubrocinctalis (Guenée, 1854) comb.n. (from Glyphodes); Alytana calligrammalis (Mabille, 1879) comb.n. (from Analyta). Epherema Snellen, 1892 stat.rev. with its type species E. abyssalis Snellen, 1892 comb.rev. is removed from synonymy with Syllepte Hübner, 1823. Ametrea Munroe, 1964 and Charitoprepes Warren, 1896 are transferred from Pyraustinae to Spilomelinae; Prooedema Hampson, 1891 from Spilomelinae to Pyraustinae; Aporocosmus Butler, 1886 from Spilomelinae to Odontiinae; Orthoraphis Hampson, 1896 from Spilomelinae to Lathrotelinae; Hydropionea Hampson, 1917, Plantegumia Amsel, 1956 and Munroe’s (1995) “undescribed genus ex Boeotarcha Meyrick” are transferred from Spilomelinae to Glaphyriinae.