We herein report a case of atypical drug-induced hypersensitivity syndrome (DIHS) involving serological reactivation of cytomegalovirus induced by carbamazepine with pulmonary and skin manifestations. These lesions were not present on admission, but developed on virus reactivation as indicated by the presence of inclusion bodies and multinucleated giant cells in alveolar cells with CD8(+) T lymphocyte infiltration on a transbronchial lung biopsy. Although the precise mechanism of DIHS remains unknown, this case suggests the crucial role of viral reactivation in pulmonary lesions in DIHS.