Pegylated recombinant human megakaryocyte growth and development factor (PEG-rHuMGDF) potently stimulates platelet production in humans, mitigates thrombocytopenia associated with nonmyeloablative chemotherapy, and reduces the need for platelet transfusions. Its long-term effect in patients, however, is not well understood. We report a patient with aplastic anaemia who received 3 cycles of PEG-rHuMGDF 3 times a week for up to 2 years. Platelet counts slightly increased 1 week after the initiation of PEG-rHuMGDF therapy, bleeding episodes decreased, and there was no need for platelet transfusion. Administration of PEG-rHuMGDF increased not only platelet numbers but also reticulocyte counts, and reduced the need for erythrocyte transfusions as well. There were no significant adverse events, and no neutralizing antibodies were detected in the patient.