The comparative cervical skin test for antemortem diagnosis of tuberculosis was done 169 times on 116 different white-tailed deer of known Mycobacterium bovis infection status. The sensitivity and specificity were 97 and 81%, respectively. The magnitude of change in skin thickness at test sites was not significantly influenced by dosage of inoculum, dissemination of the disease process, or repeated skin testing. However, the magnitude of change in skin thickness was significantly greater in deer infected for less than 109 days than in deer infected for more than 109 days. As used in the present study, the comparative cervical skin test is a sensitive method of antemortem diagnosis of M. bovis infection in white-tailed deer.