Autolytinae is revised based on available types, and newly collected specimens. Out of 170 nominal species, 18 are considered as incertae sedis, 43 are regarded as junior synonyms, and 25 are referred to as nomina dubia. The relationships of Autolytinae is assessed from 51 morphological characters and 211 states for 76 ingroup-taxa, and 460 molecular characters from mitochondrial 16S rDNA and nuclear 18S rDNA for 31 ingroup-taxa; outgroups include 12 non-autolytine syllid polychaetes. Two analyses are provided, one including morphological data only, and one with combined morphological and molecular data sets. The resulting strict consensus tree from the combined data is chosen for a reclassification. Three main clades are identified: Procerini trib. n., Autolytini Grube, 1850, and Epigamia gen. n. Proceraea Ehlers, 1864 and Myrianida Milne Edwards, 1845 are referred to as nomen protectum, while Scolopendra Slabber, 1781, Podonereis Blainville, 1818, Amytis Savigny, 1822, Polynice Savigny, 1822, and Nereisyllis Blainville, 1828 are considered nomina oblita. The following new generic synonymies are introduced: Myrianida Milne Edwards, 1845, senior synonym to Autolytus Grube, 1850; Pterautolytus Ehlers, 1907, and Regulatus Imajima, 1966, both junior synonyms to Proceraea Ehlers, 1864; and Autosyllis Imajima & Hartman, 1964, junior synonym to Virchowia Langerhans, 1879. The following new genera are described: Epigamia, Pachyprocerastea, Planicirrata, Paraproceraea, and Imajimaea. The following new species are described: Proceraea pleijeli from the Atlantic coast of Spain, Proceraea paraurantiaca from the Mediterranean and Atlantic coasts of France and Spain, and Proceraea hanssoni and Myrianida flava from Washington State, U.S.A. Proceraea madeirensis constitutes a new name for P. fasciata Langerhans, 1879 and 50 new combinations are introduced. Additionally, a number of species-level synonymies are proposed. Phylogenetic name definitions are given in parallel to a Linnean classification. Corresponding author: Arne Nygren, E-mail: arne.nygren@zool.gu.se
