A bimodal age incidence curve has been shown for Hodgkin's disease (HD). In developing countries, the first age incidence peak occurs in childhood; however, this peak is delayed until young adulthood in developed countries. This difference may reflect differences in the age of exposure to infectious agents involved in the development of HD or may suggest different etiological agents. Epstein-Barr virus (EBV) has been implicated in the pathogenesis of a proportion of HD cases. In this study, EBV association was investigated in a series of 55 pediatric HD cases from three geographical locations (United Kingdom, Brazil, and Saudi Arabia) and the relationship between country, age, sex, histological subtype, and EBV positivity was evaluated. EBV was detected in 38 cases using RNA in situ hybridization, Southern blot, or immunohistochemical analysis. No significant difference in EBV positivity by country, age, or sex was observed; however, children under 10 years of age were particularly likely to be EBV-associated. The difference in EBV association in the pediatric group compared with that observed previously for young adult HD was highly statistically significant (P < 0.0001). These results are consistent with the hypothesis that pediatric and young adult HD have different etiologies and suggest that EBV is likely to be involved in the pathogenesis of pediatric HD.