An immunophenotypic study of 17 cases of diffuse lymphocyte predominance Hodgkin's disease and 20 cases of nodular lymphocyte predominance Hodgkin's disease, along with eight of mixed cellularity and five of nodular sclerosing Hodgkin's disease, is reported. The atypical cells in nodular lymphocyte predominance Hodgkin's disease showed only minor differences from the published consensus. However, the atypical cells in diffuse lymphocyte predominance Hodgkin's disease showed an immunophenotype which was commonly B‐cell positive (59%), but in a minority of cases (24%) or epithelial membrane antigen (12%) positive; none of the cases was Ber‐H2 positive. These results do not differ greatly from our findings in nodular lymphocyte predominance Hodgkin's disease, but do diverge from the published consensus for diffuse lymphocyte predominance Hodgkin's disease. The question as to whether morphology or immunophenotype should form the primary diagnostic criterion for the definition of lymphocyte predominance Hodgkin's disease is discus