The use of radioactive phosphorus (32P) to treat the myeloproliferative disorders (chronic leukemia, polycythemia vera and essential thrombocythemia) began in 1939 when John H. Lawrence treated the first patient on the basis of work done in the laboratory animals that found localization of the radioisotope in the spleen, liver, bone and in leukemic cells sufficient to indicate a therapeutic potential. After World War II when 32P became widely available, it was used extensively to treat the chronic leukemias and polycythemia vera. Its use in the treatment of essential thrombocythemia began later in 1950. Today it is not widely used in the treatment of the chronic leukemia, if at all, its use in polycythemia vera appears to have decreased substantially and replaced by hydroxyurea, and its use in the management of essential thrombocythemia is not widespread. In each instance it has been replaced by a drug developed for use in cancer chemotherapy, and in some instances by interferon. It probably has wider use in polycythemia vera in the rest of Western Europe than in the UK, and there are cogent reasons to suggest that it may be the best tool for the treatment of polycythemia vera. Thus have we discarded a treatment modality that in polycythemia vera may be the best?