Sera of 81 white-tailed deer from south Texas and 283 white-tailed deer from Wisconsin were tested for neutralizing and hemagglutination-inhibiting antibodies to arboviruses of the Bunyamwera group. Neutralizing antibodies were detected in 100% of the Texas deer sera and hemagglutination-inhibiting antibodies were detected in 61% of those sera collected in 1969 and 78% of those sera collected in 1963. The prevalence of both neutralizing and hemagglutination-inhibiting antibodies in Wisconsin deer sera varied from 72–100% and 42–79% respectively depending on the geographic area tested in the years 1963 and 1969.