We present the case of a lung transplant recipient with disseminated infection with Bartonella henselae. In non-immunosuppressed humans, the organism typically causes a local infection that manifests itself as regional lymphadenopathy. The role of the host immune response to B henselae is critical in preventing progression to systemic disease. Only rare cases of bartonellosis in transplant recipients have been reported. We discuss aspects and difficulties of diagnosis and treatment of bartonellosis in a lung transplant recipient who suffered from a severe multisystem involvement of this disease. In our case, the initial response to therapy was unsatisfying and necessitated an extended anti-infective combination therapy, which eventually was successful.