The Epstein-Barr virus (EBV) has been demonstrated in association with cases of Hodgkin's disease (HD) indicating that, in at least in some cases, EBV may play a pathogenic role in the development of HD. To determine the prevalence of EBV in HD in a Mexican adult population, we studied 39 formalin-fixed and/or B-5, paraffin embedded samples of patients with HD, by immunoperoxidase; in situ hybridization was done in 32 of the 39 cases. We analyzed the presence of the latent membrane protein (LMP) and EBV-specific DNA sequences. Reed-Sternberg cells and mononuclear variants were positive for LMP in 28 cases (72%). LMP staining was found both on the cell surface and/or within the cytoplasm with enhancement in the Golgi area. The LMP was found in the single case of diffuse lymphocyte predominant HD, in 6/12 cases of nodular sclerosis (50%), in 10/15 cases of mixed cellularity (67%) and in all eleven cases of lymphocyte depleted HD (100%). No EBV-specific DNA sequences were found by in situ hybridization. Our results show: 1) a higher association of EBV in our population compared to the approximately 48% reported in developed countries; 2) all histologic subtypes of HD in Mexico appear to be strongly associated with EBV in contrast to the strong association with only mixed cellularity seen in Western populations; 3) the high prevalence of EBV in HD in Mexico may be a function of histology, ethnic groups, socioeconomic factors and/or geography.