A consensus classification for the waterfowl (order Anseriformes) has never been reached. There have been many revisions of the relationships within the order including those of the monotypic Australian genera. The Southern Hemisphere anseriforms comprise a large number of monotypic, endemic genera which have traditionally been linked to the established genera and tribes of the Northern Hemisphere. More recently, however, with the recognition of endemic Australian radiations of marsupial mammals (Main and Bakker 1981) and passerine birds (Cracraft 1976; Sibley and Ahlquist 1985; Christidis et al. 1988; Christidis and Schodde 1991), the affinities of the six monotypic Australian genera of anseriforms have been questioned (Delacour 1954; Frith 1955, 1964a, b, 1982; Johnsgard 196la, b, 1966; Davies and Frith 1964; Fullager 1990). In particular, whether they are more closely related to one another, or whether some or all of these monotypic genera have closer affinities with the Northern Hemisphere genera. Classification of the taxonomic relationships of the aberrant Australian endemic species may also corroborate or refute the recently advanced hypothesis of a Southern Hemisphere origin for the Anseriformes (Cracraft 1976, 1980; Livezey 1986; Olson 1988). A 307bp fragment of the mitochondrial cytochrome b gene of the 19 native Australian anseriforms and four Northern Hemisphere species was enzymatically amplified by PCR and manually sequenced. The Chicken (Gallus gallus) and Muscovy Duck (Cairinia moschatd) cytochrome b sequences were obtained from Genbank. The patterns of evolutionary dynamics within the cytochrome b gene of Anseriformes appear to conform to those reported in studies of avian and other vertebrate mtDNA. A new phylogenetic classification for the Anseriformes is proposed. The phylogenetic trees generated in this study indicate that the monotypic Australian genera, the pygmygeese and the swans and geese are members of the subfamily Anserinae which appears to represent a Southern Hemisphere radiation. Within the Anserinae, the Cape Barren Goose and Freckled Duck link most closely with each other, the Pink-eared Duck appears to be closely related to the true geese, the Musk Duck is a sister taxon to the Pink-eared Duck and may be less closely related to the Oxyura than previously thought and the Magpie Goose is the most divergent member of the Anseriformes included in this study. The Maned Duck and the remaining native Australian anseriforms are members of the established European genera and tribes of waterfowl. These species probably represent a secondary radiation of recent Northern Hemisphere invaders of Australia. Finally, the data provides some support for the theory of a Southern origin for the Anseriformes.