Four hundred and fifty‐four leukocyte transfusions from unrelated donors with chronic myelogenous leukemia were given to 128 patients during 179 febrile episodes with a median circulating granulocyte count prior to leukocyte transfusions of 80/cm. Forty‐nine per cent of the serious and life‐threatening infections responded to a combination of granulocyte transfusions and appropriate antibiotic therapy. Minor complications occurred in approximately 25 per cent of patients and more severe toxicity was seen in only 2 per cent. No deaths were attributed to leukocyte transfusions. 1975 AABB