We describe eight human cases of Bordetella bronchiseptica infection and colonization over a 15-year period. Amongst the eight patients, seven had significant underlying disease. Cat exposure was documented in three cases. Symptoms ranged from asymptomatic carriage to severe pneumonia. We could not identify a homogeneous pattern of clinical disease among symptomatic patients. Although B. bronchiseptica infection remains a rare clinical condition among humans, it should be considered as potentially pathogenic when found in airways of immunocompromised patients.