We present a case of concurrent diagnosis of acute myeloid leukemia (AML) with multiple myeloma with complex karyotype, which was successfully treated with allogeneic stem cell transplantation. A 51-year-old man with no past medical history presented with fatigue and anemia with blasts on peripheral smear. Bone marrow biopsy confirmed the simultaneous diagnosis of myeloma and AML. The patient received bortezomib and the myeloma responded well, but induction chemotherapy for the AML failed twice. He underwent an allogeneic stem cell transplant from his human lymphocyte antigen (HLA)-matched sibling, and is now disease-free approximately one year since the transplant. He has mild graft-versus-host disease (GVHD). To our knowledge, this is the first case of a patient with simultaneous AML and multiple myeloma who has undergone successful treatment with allogeneic stem cell transplantation.