Western red-backed voles are endemic to western Oregon and northern California and represent a large proportion of the rodent community in mature Douglas-fir forests. Despite their dominance in these forests, little is known about their selection of home ranges. We radiotracked 23 western red-backed voles in 3 mature, coniferous forest stands in the southern Oregon Cascades during 1994 and 1995 and estimated home range size, movements, and habitat associations. Males had larger home ranges than females and males moved farther each evening than females. Females were most active during 2 periods: shortly after dusk and before dawn. Males were active all night. Core areas for home ranges of females were characterized by deep organic soil layers and large volumes of decayed logs. Results underscore the importance of organic matter and coarse woody debris on the forest floor for maintaining populations of western-red-backed voles.