New Guinea was found to belong to the Australian Region in the classical sense of Wallace insofar as its fleas are concerned. Fifty-eight species, 28 more than hitherto recorded from New Guinea, are discussed, belonging to four families. Six species, representing three families, originated in the Oriental Region or in continental areas contiguous to it, and 52 species, comprising 15 genera of the Pygiopsyllidae, had their primordial evolutionary connections with Australia. There is much endemism of pygiopsyllids in New Guinea, all of the species and 11 of the genera occurring only there, where they are mostly associated with marsupials and murid rodents. The following genera are described as new: Orthopsylloides (type: Stivalius abacetus Jord. and Roths.), Parastivalius (type: Ceratophyllus novaeguineae Roths.), Papuapsylla (type: P. luluai n. sp.), Striopsylla (type: Stivalius rugatus Jord.), Metastivalius (type: Pygiopsylla mordax Roths.), Obtusifrontia (type: O. simplex n. sp.) and Rectidigitus (type: R. traubi n. sp.). The following new combinations for described species in these genera are proposed: in Parastivalius, Stivalius gracilentus Jord.; in Papuapsylla, Stivalius corrugis Jord., S. alticola Jord. and S. papuana Jord. & Roths.; in Metastivalius, Stivalius anaxilas M. Roths., S. lasiurus Jord. & Roths., and S. shawmayeri Jord.; and in Rectidigitus, Stivalius spooneri M. Roths. and S. ancisus Jord. In addition, descriptions of the following new species or subspecies are presented: Porribius papuanus (Ischnopsyllidae), Acanthopsylla aiyurensis, A. monticola, A. eudromiciae, A. bisinuata, Hoogstraalia novaeguineae, Pygiopsylla spinata, P. laciniosa bismarckensis, P. archboldi, P. smitiana, P. traubi, Traubia vandeuseni, T. peristigma, T. kuru, Orthopsylloides o. orthodactylus, O. o. owiensis, Parastivalius brassi, P. gressitti, Papuapsylla barretti, P. minor, Striopsylla vandeuseni, Metastivalius huonensis, M. rothschildae, M. tamberan, and Rectidigitus szentivanyi (Pygiopsyllidae).The hitherto unknown males of Acanthopsylla enderleini (Wagn.), Pygiopsylla l. laciniosa Roths., and Orthopsylloides abacetus (Jord. & Roths.) and the females of Papuapsylla corrugis (Jord.), Striopsylla rugata (Jord.), and Metastivalius anaxilas (M. Roths.) are described.