A field study was undertaken to: 1) determine if a large number of freeranging white-tailed deer (Odocoileus virginianus) could be marked with tetracycline hydrochloride (THC), and, if successful, 2) assess use of supplemental feed by deer. Shelled corn treated with THC (approximately 300 mg/0.45 kg) was distributed (18 Jul-3 Aug 1992) on a commercial hunting club in South Carolina that supplementally fed white-tailed deer. Mandibles collected from 784 hunterharvested deer (15 Aug 1992-1 Jan 1993) were evaluated for THC marks. Of those, 67.8% from the club where treated corn was deposited and 29.4% taken on surrounding properties were marked. Marked deer were found throughout the area studied (i.e., up to 5.43 km from nearest treatment site). The recovery of marked deer on and off the hunting club suggested that deer "exchange" occurred. However, because of the shape and juxtaposition of treated and untreated areas it could not be determined whether supplemental feeding was beneficial or detrimental to deer harvests on neighboring management units. This study demonstrated that tetracycline can be used to mark large numbers of free-ranging deer and suggests that delivery of oral medications such as parasiticides or vaccines may be feasible.