Information about the ecology of sympatric male deer is limited, which may influence management strategies for these species. We estimated home-range and core-area sizes and overlap, and survival of sympatric male desert mule deer (Odocoileus hemionus eremicus) and white-tailed deer (Odocoileus virginianus) in west central Texas. We captured 18 males of each species, fitted them with radio-collars, and monitored them for mortality from 2000 through 2003. We calculated home ranges for 7 males of each species in 2001 and 2002. Home-range sizes of mule deer (8.8 km²) and white-tailed deer (7.4 km²) were similar. Interspecific home-range overlap was less common than intraspecific overlap. Mean annual survival was 0.76 ( = 0.04) for mule deer and 0.80 ( = 0.06) for white-tailed deer. The high degree of home-range overlap and similar survival between the 2 deer species suggest that management targeting only 1 species may be unfeasible.