The sphaeriid fauna of Australia includes 17 species and subspecies, seven of them belonging to Musculium and ten to Pisidium. Subgeneric classification of Sphaerium problematicum Gabriel and identity of Cyclas egregia Gould are not defined. Most of the species are endemic, but one species found near Adelaide is probably an introduced Musculium lacustre (Müller). All native Musculium species are allotted to the subgenus Sphaerinova; three subgenera of Pisidium are represented (Afropisidium and Odhneripisidium by one species each and Euglesa by eight species). Two anatomically distinct and probably monophyletic groups are distinguished in Euglesa. Four species are described as new: Musculium quirindi n.sp., Pisidium (Odhneripisidium) australiense n.sp., P. (Euglesa) ponderi n.sp. and P. (E.) centrale n.sp. Descriptions of shell and anatomy as well as the data on distribution and ecology are given for each species and an identification key is provided. Some phylogenetic and zoogeographical implications are discussed.