Radio-tracking of spotted-tailed quolls Dasyurus maculatus (Marsupialia: Dasyuridae) in the forested ranges of north-eastern New South Wales revealed that home ranges were extensive, with males occupying large, overlapping ranges [minimum convex polygon (MCP) up to 757 ha] and females occupying smaller, non-overlapping territories (MCP up to 175 ha). Quolls were partly arboreal, although most activity occurred on the ground or on fallen logs. Hollow logs were most frequently used as dens, but rock crevices, burrows, tree hollows and artificial structures were also used. Individual quolls were located in up to nine different dens and, with the exception of maternal dens, rarely sheltered in the same location on successive days. The large home ranges of the spotted-tailed quoll and the non-overlapping nature of female ranges necessitate very large areas of habitat to support viable populations. Fallen timber, used extensively for shelter and in travelling, may serve to enhance the quality of habitat for the species, and should be retained by forest and wildlife managers.