An attempt has been made in an experimental group of 20 patients, with leukemia or one of the myeloproliferative disorders, to devise a safe method of splenectomy by timing the operation to coincide with optimal response to chemotherapy, preoperative bowel preparation with antibiotics to minimize infections, and availability of platelet concentrates, matched for HL-A antigens when possible, to control massive hemorrhage. The results in this experimental group were compared with a historical control group of 26 patients. Two-thirds of all the patients had chronic myelocytic leukemia, and the mean weight of the spleens removed was just over 1,800 grams. Operative mortality was 35% in the historical group and zero in the more recent group, six of whom were operated on while in blastic crisis. Splenectomy can be done safely in leukemic patients, and is not contraindicated. Future planned studies will determine its possible therapeutic role in reducing tumor burden.