We studied the trends of the Epstein-Barr virus (EBV) positivity rate in Hodgkin's disease (HD) between 1955 and 1999. The overall positivity rate gradually decreased over time [12 out of 23 (52%) in 1955-69; 18 out of 39 (46%) in 1970-84; 13 out of 44 (35%) in 1985-99; P = 0.135]. Interestingly, a marked decrease in the rate was noted in the nodular sclerosis (NS) subtype [5 out of 11 (45%); 4 out of 19 (21%); 1 out of 24 (4%); P < 0.01] but not in other classic HD [7 out of 11 (63%); 14 out of 18 (78%); 12 out of 18 (67%); P = 0.775]. Our results indicate that the EBV positivity rate in HD has decreased over time and that this trend reflected the increasing incidence of EBV-negative NS.