White-tailed deer (Odocoileus virginianus) and mule deer (O. hemionus) occur sympatrically across much of the central and western United States, including portions of west Texas. Fluctuations in populations of both species and the potential for interspecific competition indicate a need for information to aid in management of sympatric populations. We evaluated the role of vegetation and topography on habitat use by sympatric deer in west-central Texas using a geographic information system. We captured and radiocollared 50 female mule deer, 53 female white-tailed deer, and 18 males of each species, and we monitored habitat use from February 2000 to August 2002 in west-central Texas. Mule deer primarily used juniper (Juniperus spp.)-dominated habitats and habitats with elevations >870 m. White-tailed deer home ranges primarily occurred in mesquite (Prosopis spp.)-dominated areas at elevations <840 m. However, overlap did occur, because individuals of both species used or avoided specific areas. Males of both species avoided areas with dense vegetation, including those containing permanent water sources, but females of both species selected such areas, particularly during summer fawning. We did not always detect the same differences observed on the smaller core area (50% kernel home range) scale at the larger home range level, indicating that individuals made decisions about habitat use at different spatial scales. Given the differential importance of various vegetation associations to the establishment of core areas of each sex and species, maintenance of a mosaic of vegetation, particularly in lower-elevation areas and in proximity to food and permanent water, is necessary for managers to perpetuate coexistence of both species. Managers should target habitat conditions of overlap areas, particularly in core areas, for determination of potential limiting factors for both species since competition is mostly likely to occur in these areas.