We asked whether den site characteristics of Scandinavian brown bears (Ursus arctos) were related to bear sex or age by analyzing the nearest distances to human structures within 10 km, the forest composition within 50 m, and topography within 5 m of 391 winter dens used by 114 individuals during 1986–2003 in south-central Sweden. Subadult males and subadult females used more pine (Pinus sylvestris) than spruce (Picea abies) denning habitats than did adult males. Adult males selected nest dens over rock dens more strongly than did subadult males, and they selected nest dens over anthill, soil, and rock dens more strongly than did subadult females, pregnant females, or females with cubs. Topography differed among den types but showed a poor relationship with different age–sex classes of bears. Abandoned dens were located closer to plowed roads than dens used successfully all winter. Adult males denned farther from permanently occupied houses and plowed roads than did other categories of bears, perhaps because they were least tolerant of human disturbance. In general, den sites of adult males differed the most from other age–sex classes of bears.