Human herpesvirus 6 (HHV-6)-associated encephalitis or pneumonitis has been reported in immunocompetent and immunosuppressed individuals. Several MRI studies in patients with HHV-6-associated encephalitis have been presented. However, to the best of our knowledge, no studies describing thin-section CT imaging in patients with HHV-6-associated pneumonitis have been reported. Here we describe a case of HHV-6-associated encephalitis and pneumonitis that developed after bone marrow transplantation. Thin-section CT images of the chest revealed ground-glass attenuation, consolidation and centrilobular nodules in both lungs.