Bordetella bronchiseptica is a gram-negative coccobacillus, which causes respiratory infection in dogs, rabbits, and pigs, and is rarely a human pulmonary pathogen. We present 2 immunocompromised patients diagnosed with B. bronchiseptica pneumonia. To our knowledge, these are the first reports of this disease in patients with B-cell lymphoma and an orthotopic cardiac transplant. In this report, we briefly discuss the epidemiology, microbiology, and challenges in the laboratory identification of B. bronchiseptica and describe the protean imaging manifestations of this rare pulmonary infection. We also address issues related to treatment and prognosis.