The value of the combination of gemtuzumab ozogamicin (GO) and chemotherapy for the treatment of acute myeloid leukemia (AML) is currently analyzed within clinical trials. GO (6 mg/m2) and standard-dose cytarabine (100 mg/m2) is evaluated for the treatment of newly diagnosed AML in elderly patients in the SAL phase II trial. Preliminary results of the MRC AML15 trial support the application of GO 3 mg/m2 with standard- and high-dose cytarabine and anthracyclines for the treatment of de novo AML. Within this trial the addition of GO seems especially of value for favorable and intermediate cytogenetic risk groups. The combination of GO (3 mg/m2) and high-dose cytarabine (3 g/m2) is safe and more effective for the treatment of refractory AML than previous combinations from the AMLSG study group. First results prove the possibility of allogeneic stem cell transplantation after GO therapy. Initial data of a phase II trial document the safety and efficacy profile of GO within a reduced-intensity conditioning protocol applying fludarabine and total body irradiation.