Historical concepts of the generic status of the macropodines commonly known as kangaroos and wallabies are reviewed in this paper. A new diagnosis is provided for the genus Macropus, encompassing both living and fossil forms, and using cladistic principles to assess the phylogenetic value of diagnostic characters where possible. Cytological, biochemical and anatomical characters are used. Fourteen living and 11 extinct species of Macropus are recognized. Of these, 20 species have been classified into three subgenera, M. (Macropusj, M. (Osphranter) and a new subgenus, M. (Notamacro-pusj, as follows: M. (M.) giganteus, M. (M.) fuliginosus, M. (M.) mundjabus, M. (M.) pan, M. (M.) pear-soni and M. (M.) ferragus\ M. (O.) antilopinus, M. (O.) bernardus, M. (O.) robustus, M. (O.) rufus and M. (O.) pavana\ M. (N.) rufogriseus, M. (N.) eugenii, M. (N.) parryi, M. (N.) dorsalis, M. (N.) irma, M. (N.j agilis, M. (N.) greyi, M. (N.) parma, M. (N.j wombeyensis and M. (N.) thor. Four poorly known extinct species, M. dry as, M. rama, M. woodsi and M. narada, have not yet been allocated to a subgenus. Prionotemnus palankarinnicus Stirton, 1957 is shown to belong outside Macropus. Because it is the type-species of Prionotemnus, that name is not available for a subgenus of Macropus. A current synonymy is presented for fossil species and the known stratigraphic range is given for each species. A phylogeny is presented expressing our view that M. (Notamacropus) is the most plesiomorphic subgenus and M. (Macropus) is the most derived.