With 150 named species, including one Tertiary fossil, this cosmopolitan genus is the largest of the subfamily Micromyinae. The fact that most Peromyia species were described from the Holarctic Region is due to too little study elsewhere (JASCHHOF & JASCHHOF 2009). Thirty-three species, 30 endemic, were reported from New Zealand (JASCHHOF & JASCHHOF 2004), which were the only Peromyia known from the Australasian Region prior to this study. Dozens of Peromyia species may be expected to occur in Australia. Twelve species, 9 previously unnamed, are here reported from Tasmania, which increases the number of world Peromyia species to 159. I have seen specimens of a further 8 unnamed species from Tasmania. At present there is evidence for 16 Peromyia species occurring in sympatry at Warra, but further sample study and group-specific collecting will definitely uncover more. Single stands of temperate broadleaf or mixed broadleaf/coniferous forest in parts of the Palaearctic Region (Germany, Fennoscandia, Japan) may provide habitat for up to 25 sympatric PeromyiaPeromyia species (JASCHHOF & JASCHHOF 2009). The current subgeneric classification recognizes 15 species groups, two of which are endemic to New Zealand (JASCHHOF & JASCHHOF 2004, 2009) and one newly introduced here. Tasmanian PeromyiaPeromyia belong to either the new species group, representing a chiefly western Pacific radiation, or various species groups that to present knowledge are chiefly Holarctic in distribution. A key to the PeromyiaPeromyia species in Tasmania is not presented at this stage, as any key for randomly caught specimens is likely to fail due to the large number of species not yet described and named.