Data regarding the association of infection with Epstein-Barr virus (EBV) and Hodgkin's Disease (HD) are conยฏicting, with some support from cohort studies, but less coming from case-control studies. In a cohort study of impressive magnitude, Hjalgrim et al. [JNCI 92:1522[JNCI 92: -8, 2000] ] have followed 38,562 infections (determined by a positive Paul Bunnell test) between 1964 and 1995 in Denmark and Sweden. A total of 1,381 cancers were observed during 689,619 person years of follow-up (SIR 1.03, 95% CI 0.98ยฑ1.09). A statistically signiยฎcant excess of HD was noted (SIR 2.55, 95% CI 1.87ยฑ3.40), together with an excess of skin cancers (melanoma and non-melanoma both elevated) (SIR 1.27, 95% CI 1.13ยฑ1.43). The SIR for HD remained elevated for up to two decades after the occurrence of infectious mononucleosis, but decreased with time since the initial diagnosis of infectious mononucleosis (P for trend, `0.001). The SIR for HD tended to increase with age at diagnosis of infectious mononucleosis (P for trend, 0.05). Following infectious mononucleosis, the SIR for HD at ages 15ยฑ34 years was 3.46 (95% CI 2.46ยฑ4.81), which was statistically signiยฎcantly higher than for any other age group. The SIR for lung cancer was reduced (SIR 0.71, 95% CI 0.58ยฑ0.86).