The Australopacific Saprininae, containing twelve genera and forty species, are reviewed, illustrated and keyed to genera and species. Two new genera, Australopachylopus gen. n. (New Zealand, type species Saprinus lepidulus Broun, 1881) and Iridoprinus gen. n. (Australia, type species I. myrmecophilus sp. n.) and four new species: Saprinus (Saprinus) rarus sp. n. (Australia), Saprinus (Saprinus) chathamensis sp. n. (Chatham Islands, New Zealand), Saprinus (Saprinus) pseudodetritus sp. n. (Chatham Islands, New Zealand) and Saprinus (Saprinus) pacificus sp. n. (Kiribati) are described. The Saprininae fauna of the Australopacific Region is a mixture of northern invaders that most likely arrived to the region in early Cenozoic by 'island hopping' from north (Hypocaccus, Hypocacculus, several Saprinus) and truly autochthonous taxa either with uncertain phylogenetic affinities (Iridoprinus gen. n., Saprinodes Lewis, 1891, Reichardtia Wenzel, 1944, Australopachylopus gen. n.), primitive Australopacific endemics (e.g. Tomogenius Marseul, 1862) or presumed relicts (several species of Saprinus Erichson, 1834). Several Saprininae taxa (Chalcionellus aeneovirens (Schmidt, 1890); (Gnathoncus rotundatus (Kugelann, 1792); G. communis (Marseul, 1862); Euspilotus (Neosaprinus) rubriculus (Marseul, 1855); Hypocaccus (Nessus) interpunctatus interpunctatus (Schmidt, 1885); Saprinus (S.) chalcites (Illiger, 1807) and Saprinus (S.) cupreus Erichson, 1834)) were introduced into the region with human activity. We report the first cases of myrmecophily (Iridoprinus myrmecophilus gen. et sp. n.) and termitophily (Saprinus rarus sp. n.) in the Saprininae from the Australopacific Region. Lectotypes and paralectotypes of the following taxa are designated herein: Saprinus amethystinus Lewis, 1900, Saprinus apricarius Erichson, 1834, Saprinus artensis Marseul, 1862, Saprinus auricollis Marseul, 1855, Saprinus australasiae Blackburn, 1903, Saprinus bistrigifrons Marseul, 1855, Saprinus certus Lewis, 1888, Saprinus communis Marseul, 1862, Saprinus cupreus Erichson, 1834, Saprinus cyanellus Marseul, 1855, Hister cyaneus Fabricius, 1775, Saprinus dentipes Marseul, 1855, Saprinus desbordesi Auzat, 1916, Saprinus gayndahensis MacLeay, 1871, Saprinus hyla Marseul, 1864, Saprinus incisisternus Marseul, 1862, Saprinus incisus Erichson, 1842, Saprinus irinus Marseul, 1862, Saprinus laetus Erichson, 1834, Saprinus lepidulus Broun, 1881, Saprinus mastersii MacLeay, 1871, Saprinus nitiduloides Fairmaire, 1883, Saprinus pedator Sharp, 1876, Saprinus pseudocyaneus White, 1846, Saprinus rubriculus Marseul, 1855, Saprinus sinae Marseul, 1862, Saprinus tasmanicus Marseul, 1855, Saprinus tyrrhenus Blackburn, 1903, Saprinus varians Schmidt, 1890, Saprinus vernulus Blackburn, 1903, Saprinus viridanus Lewis, 1899, Saprinus viridipennis Lewis, 1901, and Saprinus westraliensis Blackburn, 1903. The synonymy of Saprinus tyrrhenus Blackburn, 1903 is revoked and the species is considered as valid (stat. n.). Seven new synonymies are proposed: Saprinus gayndahensis MacLeay, 1871 = Saprinus laetus Erichson, 1834 syn. n., Saprinus pseudocyaneus White, 1846 = Saprinus laetus Erichson, 1834 syn. n., Saprinus mastersii MacLeay, 1871 = Saprinus laetus Erichson, 1834 syn. n., Saprinus dentipes Marseul, 1855 = Hypocaccus (Baeckmanniolus) gaudens (J.L. LeConte, 1851) syn. n., Hypocaccus (Hypocaccus) vernulus (Blackburn, 1903) = Hypocaccus (Hypocaccus) sinae (Marseul, 1862) syn. n., Saprinus (Saprinus) lindrothi Dahlgren, 1968 = Saprinus (Saprinus) prasinus Erichson, 1834 syn. n., and Saprinus (Saprinus) certus Lewis, 1888 = Saprinus (Saprinus) frontistrius Marseul, 1855 syn. n. The following new records are: Euspilotus (Neosaprinus) rubriculus (Marseul, 1855) (= Saprinus gnathoncoides Bickhardt, 1909) (Australia), Saprinus (Saprinus) laetus Erichson, 1834 (Lord Howe Island) and Saprinus (Saprinus) cyaneus cyaneus (Fabricius, 1775) (Lord Howe Island and Fiji). [ABSTRACT FROM AUTHOR]