We attempted to determine what factors were common to catteries with highBartonella henselaeantibody prevalence compared with catteries with low prevalence, in order to contribute to better guidelines for the choice of a safe pet cat. The overall seroprevalence in 11 catteries from diverse geographical locations in North America in the present study was 35.8%. There was evidence ofB. henselaeexposure in all 11 homes tested, with 5 catteries being heavily infected. The distribution ofB. henselaeexposure was bimodal in catteries: either most or all cats in the home had been exposed, or very few or no cats had been exposed. Prevalence per home was also correlated with the home mean antibody titre. Flea infestation was the most important risk factor for highB. henselaeseroprevalence in the catteries we surveyed. Individual cat titres were comparable for male and female cats, cats of various ages, and cats with concurrent infectious diseases. There was no association ofB. henselaewith cattery size, husbandry practices, presence or absence of rescued cats, dog ownership, attending cat shows, routine visits to a veterinarian, and outside travel. In summary, cattery cats can be easily identified as high or low risk to new potential cat owners.