To evaluate the utility of gene rearrangement analysis, eight cases of malignant lymphoma, one case of Hodgkin's disease, two cases of angioiminunoblastic lymphadenopathy (AILD) and two cases of non-specific lymphadenitis were studied by immunohistochemical and genetic analysis. Southern blot analysis was perfon-ned by a using vacuum transfer system and a biotin labelled probe. This method was faster, safer, and more convenient than conventional methods. Gene rearrangement study showed rearranged novel bands in five of six cases of B cell lymphoma, in all cases of T cell lymphoma, and in all cases of AILD. No rearrangement of the B cell receptor(BCR) or of the T cell receptor(TCR) was seen in Hodgkin's disease or in nonspecific lymphadenitis. These results suggest that gene rearrangement analysis of BCR and TCR is a recommended method for the diagnosis of clonality in lymphoproliferative disorders. It would allow pathologists to differentiate lymphoma from polyclonal lymphoid proliferation and to provide information for cell lineage.