Bordetella bronchiseptica is a pleomorphic gram-negative coccobacillus that commonly causes respiratory tract infections in dogs. We identified nine human immunodeficiency virus (HIV)infected persons with culture-confirmed B. bronchiseptica infections (eight respiratory tract and one disseminated infection). The respiratory illnesses ranged in severity from mild upper respiratory tract infection to pneumonia. All nine patients had had at least one AIDS-defining condition before the B. bronchiseptica infection. Two patients had household contact with dogs before their illnesses, and one had household contact with cats. Infection due to B. bronchiseptica is uncommon in HIV-infected persons. Additional data are needed to fully define the spectrum of disease due to B. bronchiseptica infections and to evaluate the possibility that this infection may be acquired from pets. Treatment of B. bronchiseptica infection should be tailored to the patient and should be based on the results of susceptibility testing.