Respiratory syncytial virus (RSV) accounts for considerable morbidity among infants and elderly, that are otherwise immunocompetent. Immunocompromised haematological patients--in particular bone marrow transplant (BMT) recipients with leukopenia--are at high risk for severe, usually fatal, RSV-pneumonia. No randomized, placebo-controlled studies of aerosolized ribavirin for BMT patients with RSV-pneumonia have been conducted, or can be anticipated. We summarize existing case reports providing circumstantial evidence in favour of an active diagnostic and early therapeutic approach to these patients.