Organisms that are not known to cause serious infection in the immunocompetent population can, in fact, cause devastating illness in immunosuppressed neutropenic populations especially those who are undergoing hematopoietic stem cell transplantation (HSCT), and solid organ transplantation or a history of malignancy. One organism of interest isolated from immunosuppressed patients at our institution was Bordetella bronchiseptica. It is known to cause respiratory tract disease in the animal population which includes dogs, cats, and rabbits. This organism rarely causes serious infection in the immunocompetent population. However; in immunosuppressed patients, it can cause serious pulmonary disease. We present three cases of B. bronchiseptica pneumonia in patients with a history of malignancy.