A total of 1487 observations of nine species of arboreal mammal, Acrobates pygmaeus, Phascolarctos cinereus, Petauroides volans, Petaurus australis, P. breviceps, P. norfolcensis, Pseudocheirusperegrinus, Trichosurus caninus and T. vulpecula, were made during surveys of the vertebrate fauna of northeastern Victoria. Habitat use by each species was examined in relation to eight forest types that occur along an environmental gradient ranging from sites at high elevation with a high annual rainfall, to sites on the dry inland and riverine plains. Arboreal mammals were not evenly distributed between forest types. Three species (P. australis, P. volans and T. caninus) were mainly associated with moist tall forests; two species (P. norfolcensis and T. vulpecula) were primarily associated with drier forests and woodlands of the foothills; the remaining three species (A. pygmaeus, P. breviceps and P. peregrinus) occurred widely throughout the forests. The composition of the arboreal mammal assemblage changed along the environmental gradient, but species displayed gradual changes in abundance with forest type rather than marked discontinuities in distributional pattern. The highest overall frequencies of occurrence of arboreal mammals were in forests typically dominated by a mixture of eucalypt species. The position at first sighting of an animal, and the relative height in the forest stratum, were used to describe the micro-habitats utilised. In general, the microhabitats occupied by each species are consistent with the distribution of their known food resources.