Proteaceous leaves from two Early Tertiary sites in Tasmania are described and discussed. Based on gross leaf morphological and cuticular characters, 15 species are recognised from Oligocene lacustrine sediments at Cethana. Specimens of two taxa are not distinguishable from the extant species Telopea truncata from Tasmania and Lomatia fraxinifolia from north-eastern Queensland, and are therefore assigned to these species. Two new species of Banksieaephyllum are recognised. Ten other taxa are difficult to identify to existing genera, and are therefore referred to a new genus Proteaciphyllum. They all possess features typical of subfamily Grevilleoideae. Other, less well preserved, but probable Proteaceae from Cethana are also described. Specimens from the Leven River deposit, probably also of Oligocene age, are assigned to a new species of Orites, O. excelsoides. This species is closely related to extant O. excelsa from rainforests of north-eastern New South Wales and north-eastern Queensland. Cethana has by far the highest diversity of Proteaceae of any fossil flora described to date. The fossils also demonstrate the past association of now geographically remote taxa, and the prevalence of sclero- and xero-morphy in the family by the Oligocene.