Highly sensitive nested polymerase chain reaction was used for detecting Epstein-Barr virus (EBV) DNA in the synovial fluid of patients with rheumatoid arthritis (RA) and other arthropathies. Two out of 26 samples of the total DNA extracted from the synovial fluid of 22 RA patients were found positive. All 30 DNA samples prepared identically from the synovial fluid of the patients with arthropathies other than RA were negative. The difference in the prevalence of EBV DNA positivity between these two groups was statistically not significant. The results obtained did not support the hypothesis of the etiologic association between EBV and RA.