Human parvovirus B19 is a very common infectious pathogen in humans. In healthy subjects, B19 infection is the cause of a self-limiting subclinical erythroid aplasia, followed by rash or arthralgia. In immunocompromised patients B19 can cause chronic anemia. This report presents the case of a 19-year-old male who developed severe anemia shortly after successful allogeneic hematopoietic stem cell transplantation. His marrow showed selective erythroid aplasia, and real-time polymerase chain reaction assay confirmed parvovirus B19 infection. Despite repeated high-dose immunoglobulin treatment, he remained anemic. His hematological status markedly improved after cessation of immunosuppression. Retrospective examination of the donor's blood suggests that hematopoietic stem cells could be the source of infection.