Recent studies have indicated that nodular lymphocyte predominance Hodgkin's disease (nLP-HD) is a B-cell lymphoma. Although molecular events in the neoplastic transformation of B-cells are not well understood, Epstein-Barr virus infection and bcl-2 protein overexpression have been postulated to have etiologic roles in some lymphomas. Epstein-Barr virus has been demonstrated in the Reed-Sternberg cells of Hodgkin's disease cases (other than nLP-HD) as well as in some B-cell lymphomas; bcl-2 overexpression is found in the majority of follicular lymphomas. The biologic role for bcl-2 in HD is controversial. Some reports have indicated the presence of bcl-2 gene rearrangements, associated with the t(14;18) (q32;q21), detected by the polymerase chain reaction in HD; recent studies have failed to confirm this finding. Reports in the literature describe only a few such analyses in the nLP-HD subtype. To address these conflicting issues, we examined 12 cases of nLP-HD to determine whether bcl-2 protein expression (by immunohistochemistry) and Epstein-Barr virus (by in situ hybridization) could be detected in the Reed-Sternberg variants. None of the cases showed expression of bcl-2 protein or Epstein-Barr virus RNA in the neoplastic cells. Epstein-Barr virus does not appear to play an important role in the pathogenesis of nLP-HD. Similarly, we cannot substantiate a role for bcl-2 in the development of this type of Hodgkin's disease.