A serologic survey was conducted on an American bison (Bison bison) herd in Kansas for antibodies against Brucella spp., Leptospira interrogans serovar canicola, pomona, grippotyphosa, icterohaemorrhagiae, and hardjo, Anaplasma spp., bluetongue virus, infectious bovine rhinotracheitis virus and bovine viral diarrhea virus. There was an increase in prevalence of bluetongue antibodies from 38% in 1987 to 100% in 1989 in animals greater than or equal to 24 mo-old. Prevalence of antibodies against the other livestock pathogens were either negative or at levels associated with previous vaccination. Key words: Americam bison, Bison bison, epizootiology, serosurvey, microbial pathogens