Splenectomies have been performed on 58 patients with chronic myelogenous leukemia (CML) during the last 16 years. For the 27 patients operated upon during the first 12 years, the operative mortality was 26%. Four patients also had to be re-explored for bleeding and three required drainage of subphrenic abscesses. There has been no operative mortality in the 31 patients operated using a standardized procedure during the last four years but two had to be re-explored for bleeding and one required drainage of a subphrenic abscess. The operative risks for leukemic patients are infection, perhaps related to granulocyte abnormalities and hemorrhage in patients with thrombocytopenia or qualitative platelet abnormalities. When the splenectomy in patients with CML is timed with the patient's chemotherapy cycle, the use of local antibiotics and platelet concentrates should permit a safe operation. Survival rates were not comprised even when the patients had their splenectomy during CML-blast crisis.