SummaryA case of leukemia following the prologned use of a cytotoxic drug for a non malignant disease is reported. A 55 year old female presented with asthenia and severe anaemia. The blood smear showed immature myeloid cells and many erythroblasts. A diagnosis of crythroleukemia could be made by bone marrow biopsy. Ten years earlier this patient had been treated for scleromyxedema with D-L Melphalan. This treatment had been continued with interruptions for approximately eight years.The litterature on the occurence of acute leukemia after longstanding treatment with alkylating agents in malignant and non-malignant conditions is reviewed. The possible mechanisms of this type of leukomogenesis are discussed.