A cross-sectional epizootiologic study was conducted by mailed questionnaire to determine how the prevalence of infectious bovine keratoconjunctivitis (IBK) related to selected predisposing causes. The prevalence of IBK in Missouri during the summer of 1978 was 4.97 cases/100 cattle, with 45% of respondents reporting cases of IBK. A higher prevalence of IBK was associated with calves and yearlings, Hereford and Hereford-cross cattle, backgrounding cattle operations, and herds with a history of IBK. Vaccination of mature cattle against infectious bovine rhinotracheitis was associated with significantly higher prevalence of IBK in calves. A significantly lower prevalence of IBK was associated with dairy cattle operations, older cattle, and the winter months. There was no association between the prevalence of IBK and locale, nutrient supplementation, pasture management, use of vaccines other than infectious bovine rhinotracheitis, parasite prophylactic measures, or fly control measures.