Lymph nodes obtained from 7 HIV-positive and 20 HIV-negative patients with Hodgkin's disease were examined for the presence of Epstein-Barr virus antigens and genome. EBV antigens were observed in only 2 out of 20 HIV-negative patients, whereas lymph nodes of HIV-positive patients did not reveal evidence of EBV antigens. By in situ hybridization and Southern blot analysis, EBV genome was found in 5 out of 7 HIV-positive patients; the EBV genome was detected in the nucleus of Reed-Sternberg and Hodgkin's cells. EBV DNA was observed by in situ hybridization and Southern blot analysis in only 3 out of 20 HIV-negative patients with Hodgkin's disease. In both groups, Reed-Sternberg and Hodgkin's cells were negative for C3d EBV receptor. Our results show a statistically significant increased expression of EBV DNA in HIV-positive patients with Hodgkin's disease, as compared with HIV-negative patients with HD.