Lymphoproliferative disorders after autologous stem cell transplantation (SCT) are rare. We describe two cases of Hodgkin's disease (HD) as a late secondary neoplasia following autologous SCT for mantle cell lymphoma and B-cell chronic lymphocytic leukaemia respectively. Both HD cases were of mixed cellularity type, showed Epstein-Barr virus (EBV) positivity and followed an aggressive course. Clonal analysis of rearranged immunoglobulin genes from the primary B-cell neoplasm and the secondary HD provided evidence of separate clonal origins of the two tumours in both patients, thus excluding secondary transformation of the original B-cell clone through EBV as the causative event for development of HD.