White-tailed deer (Odocoileus virginianus) were experimentally inoculated with 60,000 or 100,000 oocysts of Eimeria mccordocki. Seven infected deer did not exhibit signs of coccidiosis although large numbers of oocysts were observed in feces after inoculation. The mean prepatent period of the parasite was 10.7 days in three deer inoculated with 60,000 oocysts and 10.0 days in four deer inoculated with 100,000 oocysts. Patent periods in these groups were 7.3 and 9.8 days, respectively.