Viral pneumonia is a common complication for patients with hematologic malignancies and after hematopoietic cell transplantation causing significant morbidity, and often mortality. Infections are predominantly caused by herpes viruses, either by reactivation of latent infection, or less commonly primary infection, or community respiratory viruses. High-resolution CT scan is useful for diagnosis but is nonspecific; generally, bronchoalveolar lavage is required. Prevention strategies are not pathogen-specific but include vaccination, chemoprophylaxis, preemptive treatment, and effective infection-prevention strategies during community outbreaks. Directed antiviral treatment is available for some pathogens. Toxicities and viral resistance are perennial challenges.