Gemtuzumab ozogamicin (GO), an anti-CD33 monoclonal antibody conjugated calichiamicin, has approved as a single agent in Japan for relapsed/refractory acute myeloid leukemia (AML). Complete remission rate was reported only as 30% in a phase II trial. GO cannot reach in bone marrow, when plenty of peripheral leukemia cells exist. Therefore, we conducted GO administration 9 days after induction chemotherapy.The institutional review board of our hospital approved this FLAG-MG therapy (G-CSF 300 μg days 1–6, fludarabin 30 mg/m2 days 2–6, AraC 1 g/m2 days 2–6, mitxantrone 5 mg/m2 days 2–4, GO 3 mg/m2 day 9) for relapsed or refractory elderly AML patients. We conducted this therapy for four refractory patients and two relapsed patients from 2008 to 2010. All six patients were induced complete remission after FLAG-MG therapy without serious complication. Four patients were now alive and two were in remission (36 and 37 months after FLAG-MG therapy). Although only a small number of cases were included in this preliminary study, this FLAG-MG therapy regimen was found to be feasible and useful even in high-risk relapsed or refractory patients.