BACKGROUND: Human parvovirus B19 infection has been known to cause chronic anemia, pure red cell aplasia, glomerulopathy and allograft dysfunction in kidney transplant (KT) recipients. The aim of this study was to evaluate the prevalence and clinical significance of B19 infection in KT recipients. METHODS: Five hundred and thirty seven serum samples from 167 KT recipients were included in the present study. The prevalence of B19 infection was based on either qualitative or quantatitive polymerase chain reaciton (PCR) with LightCycler Parvovirus B19 Quantification kit (Roche Diganostics, Mannheim, Germany). Clinical significance of B19 infection was investigated by retrospective review of hemoglobin levels and the results of kidney and bone marrow biopsies. RESULTS: Overall PCR positive rate was 18.3% (98/537) and 52 out of 167 (31.1%) KT recipients showed at least one positive PCR result. In addition, 20 out of 167 subjects (12.0%) showed PCRpositivity more than two consecutive times and they had significantly lower hemoglobin level than those with negative PCR result or only one-positive result (P < 0.0001 by ANOVA and multiple comparison). In addition, two patients (1.2%) suffered from pure red cell aplasia which was confirmed by bone marrow biopsy. Nevertheless, B19 infection did not seem to affect the graft outcome. CONCLUSIONS: The parvovirus B19 infection in KT recipeints was not uncommon and was associated with low hemoglobin level and pure red cell aplasia after KT. Therefore, routine examination for the B19 infection should be provided for the KT recipients. To the best of our knowledge, this is the first report of the incidence and clinical significance of B19 infection in Korean KT recipients.