Micro-transplantation (MST) by chemotherapy combined with granulocyte colony-stimulating factor-mobilized peripheral blood stem cell (GPBSC) infusion from HLA partial matched related donor has shown some encouraging effective therapy for acute myeloid leukemia (AML). However, the outcome of human leukocyte antigen (HLA) fully mismatched unrelated donor-derived MST in such patients is still unknown. In the present study, we compared the efficacy of human leukocyte antigen (HLA) fully mismatched unrelated donor-derived MST and partly matched related donor-derived MST in AML of 126 patients from 2 centers in China, These patients, aged 16 to 65years, were given 3 or 4 courses of MST, which consisted of a high dosage cytarabine followed by GPBSC from unrelated donor or related donor. There was a statistically significant difference in 3-year leukemia-free survival and 3-year overall survival between the unrelated and the related group. The non-treatment-related mortality rates of patients, and other adverse complications, were no different in two groups. In conclusion, unrelated donor-derived MST is believed to be a safe treatment, with efficacy similar to or higher than related donor-derived MST. This result provides support for the potential of MST for expanding the donor selection. However, the specific mechanism of action needs further study. This article is protected by copyright. All rights reserved.