An 88-year-old man with autoimmune hemolytic anemia (AIHA) who had been treated with low dose prednisolone developed a sudden worsening of his anemia accompanied by reactivation of Epstein-Barr virus (EBV). We established EBV-infected spontaneous lymphoblastoid cell lines (LCL), performed an enzyme-linked immunosorbent spot assay, and confirmed a significantly suppressed EBV-specific cytotoxic T-cell (CTL) response to the LCL. EBV reactivation might have been brought about by suppressed CTL activity which could have been due to low dose PSL administration or aging. Since the EBV-DNA titer decreased as AIHA improved, we concluded that EBV might have played a role in the development of anemia.