We describe a case of B-prolymphocytic leukaemia (B-PLL) who, following a long-lasting remission with fluradabine, developed a Hodgkin's lymphoma (HL) with bone marrow involvement. A 75-yr-old male was found to have a lymphocytosis [white blood cell (WBC) count = 146 x 10(9) L(-1)], small volume axillary lymphadenopathy, and hepatosplenomegaly. The majority of circulating lymphocytes had a round nucleus and prominent single nucleolus. The patient did not respond to chlorambucil and then received fludarabine, achieving a good response lasting for 5 yr, when he manifested with B symptoms and pancytopenia. A diagnosis of HL in the bone marrow was made based on histology (Reed-Sternberg cells) and immunohistochemistry (CD30+, CD15+). Epstein-Barr virus (EBV) studies were negative. The patient was treated with chemotherapy but died 6 months later from disease progression.