Thirteen radio equipped gray foxes (Urocyon cinereoargenteus) were located by triangulation during 24-hour tracking periods on the Savannah River Site, Aiken, South Carolina, between 22 March 1985 and 24 May 1986. Diurnal and nocturnal habitat use was evaluated for each sex within seasonal (pup rearing N ~ 6, dispersal and mating N = 9, and denning N =1) and comprehensive (N = 13) home ranges. Proportional use of available habitats was not observed for 13 of 16 sex-temporal groupings (P < 0.05). Tests for relative use of 7 available habitat types demonstrated diurnal preference by both sexes of 5- to 14-year-old pine stands and, depending on sex and season, random or preferred use of these stands at night. Males and females in most seasonal groupings used ≥ 5-year-old pine stands less than expected during the day and randomly used them at night. Less than expected use of the 0- to 4-year-old pine/old field category was frequently exhibited, depending on sex and season. All other habitat categories varied in relative use depending on sex and season. Differences in habitat use occurred between sexes within seasons and between seasons within sexes. Seasonal differences in habitat use probably resulted from seasonally changing food habits, cover requirements, and reproductive behaviors. Intersexual differences in habitat use resulted from female habitat selection during denning and pup rearing seasons.