We report an isolated pancreas transplant recipient on immunosuppressive therapy with parvovirus B19 infection. He presented with a chronic transfusion-dependent anemia, unresponsive to erythropoietin therapy. Bone marrow cytomorphology was highly suggestive of parvovirus pure red cell aplasia, which was confirmed with polymerase chain reaction positive for parvovirus B19 DNA from peripheral blood. The anemia responded briskly and reticulocyte counts improved from 0.0% to 17.0% within 1 week after the administration of intravenous immunoglobulin. We discuss the difficulty of serological diagnosis in such cases, the importance of using techniques that directly identify the virus, and taking measures that may prevent recurrence.