We have correlated histologic type of Hodgkin's disease, degree of Hodgkin and Reed-Sternberg cell infiltration, percentage of Hodgkin and Reed-Sternberg cell positivity for latent membrane protein, immunophenotype of Hodgkin and Reed-Sternberg cells, and immunoglobulin heavy chain (IgH) gene rearrangements detected by polymerase chain reaction (PCR) in 56 unselected Hodgkin's disease cases. Two protocols were used for amplification of IgH gene using Fr2 or Fr3 V-region primers, in conjunction with nested primers directed to the JH region. PCR products were run on polyacrylamide gels. Immunohistochemical studies were performed on paraffin sections using monoclonal antibodies for CD20 and latent membrane protein, and polyclonal antibody to CD3. Using both primer combinations we detected a definitive clonal band in 23.2% of the Hodgkin's disease cases. Clonal IgH rearrangements were detected in 23.6% of nodular sclerosis type and in 28.5% of mixed cellularity type. Using a highly sensitive method such as PCR, more than 20% of unselected cases of Hodgkin's disease were found to contain B-cell clonal proliferations, but there was no correlation between histological and immunological parameters and molecular analysis results.