Lesser prairie chicken (Tympanuchus pallidicinctus) abundance, like that of most grassland birds, has declined rangewide for decades. Although habitat loss and degradation are likely ultimate causes for this decline, infectious agents, particularly microparasites, could be proximate contributors. No surveys of pathogenic bacteria or viruses have been published for this species. We surveyed 24 free-living lesser prairie chickens from Hemphill County, Texas (USA), for evidence of exposure to Salmonella typhimurium, S. pullorum, Mycoplasma gallisepticum, M. synoviae, Chlamydophila psittaci, and the avian influenza, Newcastle disease, infectious bronchitis, and reticuloendotheliosis viruses. Two of 18, and eight of 17 samples were seropositive for the Massachusetts and Arkansas serotypes of infectious bronchitis virus, respectively. Five of the eight positive individuals were juveniles, two of which were seropositive for both serotypes. All other serologic and genetic tests were negative. Because the ecological significance of these results is unknown, the pathogenesis, transmission, and/or population-level influences of infectious bronchitis and related avian coronaviruses for lesser prairie chickens deserves further study.