There have been few reports of large granular lymphocyte (LGL) leukemia with neutropenia complicated with pure red cell aplasia (PRCA) that developed after human parvovirus (HPV) B19 infection. We report here the case of a 35-year-old female who developed HPV B19-associated PRCA with T-LGL leukemia. LGL count of peripheral blood was lower than 2 x 10(9) l(-1), although phenotypic analysis of LGL showed CD3+, CD16-, CD56-, CD57+ with double positive for CD3 and CD57, and genetic study showed the clonal rearrangement of T-cell receptor gene. Microscopically, the patient's bone marrow showed characteristic giant proerythroblasts. A serologic study of HPV B19 was positive for IgM, but negative for IgG, with a positive result on Dot-blot hybridization assay for HPV B19 DNA. Severe anemia and reticulocytopenia ameliorated without treatment 10 days after the initial examination, but slight anemia, neutropenia, a moderate increase of LGL counts with rearrangement of TCR gene, and positive result of HPV B19 DNA has persisted 7 months after the initial examination. We suggest that this viral infection may play an etiologic role in some patients with LGL leukemia who develop PRCA.