Serologic tests for leptospiral antibodies were conducted on 3236 sera from white-tailed deer killed in Pope County, Illinois from 1957 through 1968. Antibodies were detected to Leptospira pomona in 162 (5.0%) samples. The percentage of reactors was significantly less in female deer and in fawns of both sexes. The distribution of reactors in the county showed a reactor incidence (reactors/1000 deer tested) of 103 in areas with lower deer densities and higher cattle densities. The incidence in areas with more deer and fewer cattle ranged from 14 to 44.