To study changes in the clinico-pathological features of malignant lymphomas in Japan, the histopathological and clinical features of 71 cases of Hodgkin's disease and 49 cases of nodal follicular lymphoma occurring in Nagoya were compared in three different periods (1965-71, 1972-78 and 1979-85). The proportional frequency of Hodgkin's disease among total lymphomas (10%) and that of follicular lymphoma among non-Hodgkin's nodal lymphomas (18%) did not vary over the study period. As to the histological patterns of Hodgkin's disease, the relative frequency of the nodular sclerosis (NS) type, which is relatively common in young women, increased, but that of other types decreased in the more recent periods. For follicular lymphoma, the relative frequency of the completely follicular type, which is more common in the United States than in Japan, increased. The five-year survival rate in patients with follicular lymphoma improved more recently even after adjusting for the effects of other prognostic factors. This recent increase in survival rates may be due partly to the recent improvement in cancer treatment, but is also related to the recent increase in patients with better prognostic features, i.e. the NS type of Hodgkin's disease. These variations over time suggest that the patterns of malignant lymphomas in Japan might be gradually changing, probably because of westernization, as seen in cancers of other organs.