During the 1920s, several exotic deer species were introduced to Little Saint Simons Island (LSSI), Georgia, an approximately 4,340-ha, privately owned barrier island. Currently, the only exotic cervid inhabiting the island is the fallow deer (Dama dama). The economic value of fallow deer hunting, along with concerns over altered ecological communities, have triggered the need for research on this population and its potential ecological impacts. From 2003-2006, I examined the populations demographics, health, food habits, and spatial ecology. Antler and body measurements of fallow deer on LSSI were smaller than those from other populations. Density estimates ranged from 36.4-62.4 deer/km, and the sex ratio was estimated at 1.1 bucks to 1 doe. No clinical signs of disease were noted, parasite burdens were low, and overall the population was in good health. Parasite species were similar to those found in white-tailed deer (Odocoileus virginianus) with the exception of two abomasal nematodes. Fallow deer foraged on a wide variety of food items, preferring grasses and mast of Quercus spp. Data from deer instrumented with global positioning system (GPS) collars indicated that adult female home ranges averaged 130.3 0.45 ha. Male home ranges were more variable, ranging from 56.9 to 354.8 ha. Deer avoided salt marsh habitats, but among the other habitats represented on LSSI, no general patterns in preference were observed. Fallow deer have adapted well to the barrier island ecosystem and competitive advantages apparently have helped to exclude native white-tailed deer. However, the population likely has exceeded carrying capacity for LSSI and a reduction in herd size may be warranted.