Cutaneous manifestations of Waldenström's macroglobulinaemia (WM) include purpura, ulcers, urticaria, leukocytoclastic vasculitis, and immunobullous dermatoses. No association has been reported previously of WM and hepatitis B virus (HBV) infection. A 40-year-old female HBV carrier was admitted to hospital because of generalized oedema, oliguria, haematuria, hypertension, fever and blood-tinged sputum. Cutaneous manifestations included generalized petechiae, palpable purpura mainly on the legs, multiple necrotic ulcerations and gangrenous changes on the toes, and necrotic, giant confluent reticulate purpura on the trunk surmounted by several tense bullae. Laboratory investigations revealed monoclonal gammopathy of IgM kappa type (6.7 g/L), membranoproliferative glomerulonephritis associated with HBV infection, Bence Jones proteinuria, and an increased number of abnormal plasmacytoid cells in the bone marrow. Pathologic examination demonstrated immune complex-mediated vasculitis with deposits of IgM in the walls of dermal vessels and secondary subepidermal bulla formation. HBV infection may have caused WM or modified the clinical course in this fatal case.