Patients with uremia are susceptible to viral infections, especially to Epstein-Barr virus (EBV). Sixty-one patients with end-stage renal diseases on chronic hemodialysis (HD), 14 patients with impaired renal function (CRF), and 27 healthy controls were studied with regard to EBV infection. Uremic patients (HD and CRF) had a significantly higher incidence of EBV infection and higher titers of anti-EBV VCA-IgG antibody than healthy controls. The anti-EBNA-1 titer was significantly higher in patients whose dialysis period was more than 3 months than in whom the dialysis period was 3 months or less. Immunoblotting analysis also showed stronger EBNA-1 signals in hemodialysis patients than EBNA-2, which was strongly detected in the CRF group and in healthy controls. EBV DNA was detected by Southern blot hybridization after PCR amplification of peripheral leukocytes, and occurred at a greater incidence in hemodialysis patients than in the other groups. Taken together, these results demonstrated that hemodialysis patients had persistent EBV infection.