Detailed knowledge of how individuals use space when active and while sheltering is crucial to understanding the habitat requirements of a species. I present the first home-range estimates for bobucks, Trichosurus cunninghami, that are based on both nocturnal and diurnal radio-tracking fixes. I tracked 37 individuals (14 adult females, 14 adult males, three subadult females and six subadult males) between mid-1999 and late 2003 in a forest patch in the Strathbogie Ranges, south-eastern Australia. I collected a total of 9562 diurnal fixes (mean 309 fixes per adult) and 5211 nocturnal fixes (mean 169 fixes per adult). All individuals used multiple den-trees; adults used a mean of 7.2 den-trees per individual. Adult bobucks of both sexes had a mean home-range size of 6.0 ha. There were no significant differences in the mean number of den-trees used or in the mean home-range size of adult males and females. Subadults used significantly fewer den-trees and had significantly smaller home ranges than adults. This study demonstrates the importance of large and long-term datasets in accurately determining the habitat requirements of a population.