Duplication of the Philadelphia (Ph1) chromosome is known to occur in the course of chronic granulocytic leukaemia (1). Usually, if not always, this acquired cytogenetic development precedes or occurs with an acute transition of chronic granulocytic leukaemia. The acute phase of chronic granulocytic leukaemia with duplication of the Ph1 chromosome is frequently associated with the development of enlarged myeloid lymph nodes, resembling reticulum cell malignancies on histologic examination (2). We present here a pertinent case report of a 39-year-old woman with typical chronic granulocytic leukaemia whom we have followed for 7 years. She was treated with successive courses of busulfan