Donor leukocyte infusion (DLI) has been successfully used for some life-threatening viral infections after stem cell transplantation (SCT). We describe here the first case of DLI treatment for cytomegalovirus (CMV) retinitis. A 49-year-old female patient with AML, M1 underwent SCT with a reduced-intensity conditioning regimen from HLA-haploidentical son. On day +140, the patient developed CMV retinitis of her left eye despite the continuing antiviral therapy. DLI at a dose of 1 x 10(5) CD3+ cells/kg was added to ganciclovir and foscarnet therapy. Eighteen days after the DLI, the funduscopic findings revealed improvement of the retinitis and the development of vitreous inflammation. Simultaneously, the number of CD4+ cells in the peripheral blood rapidly increased. Thus, we consider it likely that DLI induced a local immune response against CMV antigens, which resulted in the immune recovery vitritis. This case suggested the potentiality of DLI for the treatment of CMV retinitis.