A histological review of 271 cases of nodular sclerosing Hodgkin's disease, patients presenting with clinical Stage I, II and III disease but not subjected to a staging laparotomy, has been undertaken. Cases were categorised according to the cytological appearances of the cellular nodules and the degree of sclerosis was examined. Cytological subtypes with extensive and easily recognised areas of lymphocyte depletion or numerous pleomorphic Hodgkin's cells were associated with a decreased survival and clinical stage did not appear to be a good indicator of prognosis in these patients. Pronounced nodal sclerosis was associated with a higher relative frequency of mediastinal disease and the lymphocyte-depleted cytological subtypes.