We describe the successful treatment of a pregnant patient with chronic myelogenous leukemia in chronic phase by using only leukapheresis. Following 20 leukapheresis procedures initiated during the 13th week of gestation and performed over approximately 7 weeks, the patients white blood cell count dropped from 242,000/microl to 19,300/microl. The WBC remained stable over the ensuing 17 weeks until the time of delivery. The patient gave birth by cesarean section to a healthy 2,640 g boy at 37.5 weeks of gestation. This is the second report of the successful use of leukapheresis alone for chronic myelogenous leukemia in chronic phase during the first half of pregnancy. We conclude that where leukapheresis is available, it may provide an alternative treatment to chemotherapy or alpha-interferon, especially in light of their potential teratogenic and leukemogenic side-effects.